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La dopamine est un neurotransmetteur important dans le fonctionnement des ganglions de la base, région du cerveau impliquée dans la fonction motrice et l’apprentissage. Un dérèglement de la dynamique de la dopamine peut être à l’origine de différentes pathologies neurologiques, telles que la maladie de Parkinson et le trouble de déficit de l’attention avec ou sans hyperactivité (TDAH). La lévodopa, un précurseur de la dopamine, est utilisée pour réduire les symptômes associés à la maladie de Parkinson, sans action directe sur ses causes. La lévodopa est très efficace au début de la maladie, mais la durée de son effet ainsi que son index thérapeutique diminuent avec la progression de la dénervation induite par la maladie. Ces changements compliquent considérablement l’optimisation des régimes posologiques. Le méthylphénidate, quant à lui, est administré pour réduire les symptômes du TDAH et agit entre autres en bloquant la recapture de la dopamine. Bien que les données confirment une certaine implication de la dopamine dans le TDAH, son étiologie exacte demeure inconnue. Peu d’études ont cerné l’effet de la lévodopa sur le système dopaminergique des ganglions de la base et son évolution avec la progression de la maladie. Aussi, bien que le TDAH ait suscité beaucoup d’intérêt, rares sont les études quantitatives de nature mécanistiques sur le sujet. L’approche de modélisation mathématique utilisée dans cette thèse s’inscrit dans un effort global visant l’optimisation de la lévodopa et du méthylphénidate, appuyé par l’élucidation des mécanismes impliqués dans la maladie de Parkinson et dans le TDAH. En adoptant une approche de pharmacologie quantitative des systèmes (QSP), nous avons développé un modèle intégratif du système dopaminergique des ganglions de la base, avec l’objectif d’élucider les mécanismes impliqués, d’évaluer l’impact de la dopamine chez dessujets souffrant de Parkinson ou de TDAH, et recevant ou non un traitement, et enfin de guider objectivement l’exercice d’optimisation des régimes posologiques. À notre connaissance, c’est le premier cadre unificateur de modélisation qui s’adresse à ces deux pathologies. Le modèle développé dans cette thèse est composé de trois sous-modèles : le premier décrit la pharmacocinétique du médicament concerné, soit la lévodopa ou le méthylphénidate ; le deuxième exprime mathématiquement les différents mécanismes impliqués dans la dynamique de la dopamine ; le troisième représente la complexité de la neurotransmission dans les ganglions de la base. Avec des adaptations appropriées, nous avons appliqué ce même modèle au contexte de la maladie de Parkinson et au TDAH, ainsi qu’à leurs thérapies respectives. Pour représenter physiologiquement la maladie de Parkinson, nous avons intégré dans le modèle l’évolution de la perte neuronale ainsi que les différents mécanismes de compensation qui en résultent. La fréquence de tapotement des doigts est utilisée comme mesure clinique de la bradykinésie, définie comme le ralentissement des mouvements chez les patients parkinsoniens. Le modèle développé se base sur les connaissances actuelles de la pathophysiologie et pharmacologie du Parkinson, assurant ainsi sa validité en comparaison à des observations expérimentales et cliniques. Ensuite, à l’aide de ce modèle, les relations non-linéaires entre la concentration plasmatique de lévodopa, la concentration en dopamine dans le cerveau et la réponse à une tâche motrice sont étudiées. Le rétrécissement de l’index thérapeutique de la lévodopa au cours de la progression de la maladie dû à ces non-linéarités est investigué. Enfin, pour assurer l’aspect translationnel de notre approche, nous avons développé une application web à laquelle ce modèle a été intégré. Cette application sert de preuve de concept à un outil facilitant l’optimisation et l’individualisation des régimes posologiques. Pour l’étude du TDAH, nous avons adapté le modèle du système dopaminergique en y intégrant la libération tonique et phasique de la dopamine, cette dernière se produisant durant une tâche d’apprentissage par renforcement. Des individus virtuels ont été créés avec et sans déséquilibre du ratio tonique/phasique de la dopamine. En simulant une tâche de réponse à des stimuli dans un contexte de déséquilibre de la dopamine, le modèle nous a permis d’observer des symptômes similiaires à ceux de patients réels souffrant de TDAH. Finalement, la réponse au méthylphénidate résultant de l’inhibition de la recapture de la dopamine, à travers différents scénarios d’apprentissage a aussi été étudiée. Le développement d’une métrique nous a permis de différencier les répondants des non-répondants, et ainsi de mettre en évidence l’implication possible d’un apprentissage excessif chez les nonrépondants. Une meilleure compréhension de la réponse au méthylphénidate permettrait d’éviter la surmédication chez les non-répondants et d’aider les cliniciens dans leur pratique. Malgré la complexité du système dopaminergique et des traitements associés, cette thèse est un pas en avant dans la compréhension des mécanismes sous-jacents et de leur implication dans la thérapie. Ces avancées ont été réalisées en adoptant une approche de pharmacologie quantitative des systèmes, associée à une modélisation neurocomputationnelle du domaine du génie électrique, et complétée par un aspect de transfert au chevet du patient. Ce n’est qu’en transcendant ainsi les frontières disciplinaires qu’une visée aussi globale et intégrative est possible, afin de faire face aux défis multidimensionnels du système de la santé., Dopamine is an important neurotransmitter of the basal ganglia, a region of the brain involved in motor function and learning. Disruption of dopamine dynamics can cause various neurological conditions, such as Parkinson’s disease and attention deficit hyperactivity disorder (ADHD). Levodopa, a dopamine precursor, is used to reduce the symptoms associated with Parkinson’s disease, without directly alleviating its causes. Levodopa is very effective in the early stages of the disease, but its effect duration along with its therapeutic index decrease with disease-induced denervation. These modifications further challenge determination of optimal dosing regimens of levodopa. In the case of ADHD, methylphenidate is administered to reduce its symptoms by, among other things, blocking dopamine recapture. Although evidence supports involvement of dopamine in ADHD, its exact etiology remains unknown. Few studies have investigated the effect of levodopa on the basal ganglia dopaminergic system and how it evolves with disease progression. Also, although ADHD has received a lot of interest, few quantitative studies of a mechanistic nature have been conducted on the subject. The mathematical modeling approach used in this thesis is part of an overall effort to optimize levodopa and methylphenidate, supported by the elucidation of the mechanisms involved in Parkinson’s disease and ADHD. Using a quantitative systems pharmacology (QSP) approach, we have developed an integrative model of the basal ganglia dopaminergic system, with the objective of elucidating the mechanisms involved, assessing the impact of dopamine in subjects with Parkinson’s or ADHD, with and without treatment, and objectively guiding the dosing regimens optimization. To the best of our knowledge, this is the first unifying modeling framework that addresses at the same time these two pathologies and their therapies. The model developed in this thesis includes three sub-models: the first one describes the drug pharmacokinetics, either levodopa or methylphenidate; the second one translates mathematically the different mechanisms involved in the dopamine dynamics; the third one is a computational representation of the complexity of neurotransmission in the basal ganglia. With appropriate adaptations, we have applied this same model to the context of Parkinson’s disease and ADHD, as well as to their respective pharmacotherapies. In order to physiologically represent Parkinson’s disease, we have integrated the denervation process in the model as well as the resulting compensation mechanisms. The finger tapping frequency is used as a clinical endpoint of bradykinesia, defined as the slowing of movements. The developed model is based on up-to-date knowledge of the pathophysiology and pharmacology of Parkinson’s disease, thus ensuring its validity in comparison with experimental and clinical observations. Using this model, the non-linear relationships between plasma levodopa concentration, dopamine concentration in the brain and response to a motor task were studied. The narrowing of levodopa therapeutic index during the progression of the disease due to these non-linearities was investigated. Finally, to ensure the translational aspect of our approach, we developed a web application in which this model was integrated. This application serves as a proof of concept for a tool aimed to facilitate the optimization and individualization of dosing regimens. For the study of ADHD, we adapted the developed model by integrating tonic and phasic dopamine release, the latter occurring during a reinforcement learning task. Virtual individuals were created with and without dopamine imbalance in the tonic/phasic ratio. By simulating a stimulus-response task, we observe ADHD-like symptoms among virtual patients with dopamine imbalance. Finally, the response to methylphenidate resulting from dopamine recapture inhibition, through different learning scenarios, was also studied. The development of a metric allowed us to differentiate responders from non-responders, and thus to highlight the possible implication of excessive learning in non-responders. A better understanding of methylphenidate response would help avoid overmedication in non-responders and assist clinicians in their practice. Despite the complexity of the dopaminergic system and its associated therapies, this thesis is a step forward in understanding the underlying mechanisms and their involvement in pharmacotherapy. These advances were achieved by adopting a quantitative systems pharmacology approach, combined with neurocomputational modeling borrowed from the electrical engineering field, and complemented by a translational bedside aspect. It is only by transcending disciplinary boundaries and adopting such an integrative approach that this ultimate goal of having a real impact on the multifaceted health system is possible.

Level of motivation, responsiveness to rewards and punishment, invigoration of exploratory behaviours, and motor performance are subject to daily fluctuations that emerge from circadian rhythms in neuronal activity of the midbrain’s dopaminergic system. While endogenous circadian rhythms are weak in the ventral tegmental area and substantia nigra pars compacta, daily changes in expression of core clock genes, ion channels, neurotransmitter receptors, dopamine-synthesising enzymes, and dopamine transporters, accompanied by changes in electrical activity, are readily observed in these nuclei. These processes cause dopamine levels released in structures innervated by midbrain dopaminergic neurons (e.g., the striatum) to oscillate in a circadian fashion. Additionally, growing evidence show that the master circadian clock located in the suprachiasmatic nucleus of the hypothalamus (SCN) rhythmically influences the activity of the dopaminergic system through various intermediate targets. Thus, circadian changes in the activity of the dopaminergic system and concomitant dopamine release observed on a daily scale are likely to be generated both intrinsically and entrained by the master clock. Previous studies have shown that the information about the value and salience of stimuli perceived by the animal is encoded in the neuronal activity of brain structures innervating midbrain dopaminergic centres. Some of these structures themselves are relatively autonomous oscillators, while others exhibit a weak endogenous circadian rhythm synchronised by the SCN. Here, we place the dopaminergic system as a hub in the extensive network of extra-SCN circadian oscillators and discuss the possible consequences of its daily entrainment for animal physiology and behaviour.

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) The interaction between neurotransmitters triggers several possibilities for synaptic integration. Evidence suggests that the cerebellum is involved in processing both motor and non-motor functions. However, the interaction between the cerebellar histaminergic and dopaminergic systems in the modulation of these functions is unclear. This study aimed to investigate the role of the cerebellar dopaminergic system in motor behavior and motor learning, and in the acquisition of aversive emotional memory in mice, as well as to investigate the interaction of the cerebellar histaminergic and dopaminergic systems in the same functions. For this, the animals received the implantation of a guide cannula into the cerebellar vermis through stereotaxic surgery. After recovery they underwent the drug microinjection procedure, with an administration of 0.1µl of the drug, depending on the experimental group in which they were allocated. To evaluate the motor performance and motor learning of the mice, the time spent on the Rota-rod and the crossing latency on the balance beam were measured in five steps (habituation, microinjection, stage 1, stage 2, stage 3). To assess the acquisition of emotional memory, the mice underwent the inhibitory avoidance test, and the time to cross from the light side to the dark side was measured at all exposures. After the end of the experiments, the animals received a deep dose of anesthesia, underwent cardiac perfusion with 4% paraformaldehyde fixative in phosphate buffered saline (PBS), and their brains were stored. Statistical analysis of behavioral data was performed by repeated measures analysis of variance. Tukey's post hoc test was used in case of significant differences in the analysis of variance. Intravermis cerebellar administration alone of Dopamine and SCH 23390 (D1 dopamine antagonist) had no effects on motor behavior, motor learning and emotional memory in this study. The microinjection of Eticlopride (D2 dopamine antagonist) had no effect on motor behavior and motor learning, but the highest dose improved the acquisition of emotional memory in the inhibitory avoidance task (p=0.01). The combined injection of Histamine and SCH23390 had no effect on emotional memory acquisition in inhibitory avoidance. However, animals that received this drug combination showed a significant decrease in performance and motor learning in rotarod (p=0.02), and a tendency to increase the balance beam crossing time (p=0.07). The combined injection of Histamine and Eticlopride had no effect on motor learning, but it improved the emotional memory acquisition in the inhibitory avoidance test in mice in this study (p=0.07). In this study, we identified that Histamine administration was able to potentiate the action of sub-effective doses of D1 and D2 dopaminergic antagonists in different experimental models, which strengthens the hypothesis of interaction of these systems in the processing of motor and non-motor functions. D1 receptors seem to be predominantly related to motor learning processes, while D2 receptors seem to be predominantly related to the processing of aversive memories. A interação entre neurotransmissores pode gerar diversas possibilidades para integração sináptica. Evidências sugerem que o cerebelo está envolvido no processamento de funções motoras e não motoras. Contudo, a interação entre o sistema histaminérgico e dopaminérgico cerebelar na modulação dessas funções é pouco explorada. Este estudo teve como objetivo investigar o papel do sistema dopaminérgico cerebelar no comportamento motor e aprendizado motor, e na aquisição de memória emocional aversiva em camundongos, assim como investigar a interação dos sistemas histaminérgico e dopaminérgico cerebelar nas mesmas funções. Para isso, os animais receberam a implantação de uma cânula guia no vérmis cerebelar por meio de cirurgia estereotáxica, e após recuperação passaram pelo procedimento de microinjeção de drogas no volume de 0.1µl, a depender do grupo experimental no qual estavam alocados. Para avaliar o desempenho motor e aprendizagem motora dos camundongos, o tempo de permanência no Rota-rod e a latência de travessia na trave de equilíbrio foram mensurados em cinco etapas (habituação, microinjeção, estágio 1, estágio 2, estágio 3). Para avaliação da aquisição de memória emocional, os camundongos passaram por teste de esquiva inibitória, e o tempo de travessia do lado claro para o lado escuro foi mensurado em todas as exposições. Após o término dos experimentos, os animais receberam uma dose profunda de anestesia, passaram por perfusão cardíaca com paraformaldeído fixador 4% em tampão fosfato salino (PBS), e seus encéfalos foram armazenados. A análise estatística dos dados comportamentais foi feita por análise de variância de medidas repetidas. O teste post hoc de Tukey foi utilizado em caso de diferenças significativas na análise de variância. A administração intravermis cerebelar isolada de Dopamina e SCH 23390 (antagonista dopaminérgico D1) não apresentaram efeitos sobre o comportamento motor, aprendizagem motora e memória emocional nesse estudo. A microinjeção de Eticlopride (antagonista dopaminérgico D2) não apresentou efeitos sobre o comportamento motor e aprendizagem motora, porém a dose mais alta provocou melhora na aquisição de memória emocional em tarefa de esquiva inibitória (p=0.01). A injeção combinada de Histamina e SCH23390 não apresentou efeitos sobre a aquisição de memória emocional na esquiva inibitória. No entanto, animais que receberam essa combinação de drogas apresentaram uma piora significativa da performance e aprendizagem motora em rotarod (p=0.02), e uma tendência ao aumento no tempo de travessia da trave de equilíbrio (p=0.07). A injeção combinada de Histamina e Eticlopride não apresentou efeitos sobre a aprendizagem motora, porém provocou melhora na aquisição de memória emocional no teste de esquiva inibitória em camundongos neste estudo (p=0.07). Neste estudo, identificamos que a administração de Histamina foi capaz de potencializar a ação de doses sub efetivas dos antagonistas dopaminérgicos D1 e D2 em diferentes modelos experimentais, o que fortalece a hipótese de ação conjunta desses sistemas no processamento de funções motoras e não motoras. Receptores D1 parecem ser predominantemente relacionados à processos de aprendizagem motora, enquanto receptores D2 parecem ser predominantemente relacionados ao processamento de memórias aversivas. Processo nº 2017/24879-6, Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

(1) Background: Rheumatoid arthritis (RA) is a common systemic autoimmune disease affecting many people and has an unclear and complicated physiological mechanism. The competing endogenous RNA (ceRNA) network plays an essential role in the development and occurrence of various human physiological processes. This study aimed to construct a ceRNA network related to RA. (2) Methods: We explored the GEO database for peripheral blood mononuclear cell (PBMC) samples and then analyzed the RNA of 52 samples (without treatment) to obtain lncRNAs (DELs), miRNAs (DEMs), and mRNAs (DEGs), which can be differentially expressed with statistical significance in the progression of RA. Next, a ceRNA network was constructed, based on the DELs, DEMs, and DEGs. At the same time, the Kyoto Encyclopedia of Genes and Genomes (KEGG) and Gene Ontology (GO) analysis were used to validate the possible function of the ceRNA network. (3) Results: Through our analysis, 389 DELs, 247 DEMs, and 1081 DEGs were screened. After this, a ceRNA network was constructed for further statistical comparisons, including 16 lncRNAs, 1 miRNA, and 15 mRNAs. According to the GO and KEGG analysis, the ceRNA network was mainly enriched in the mTOR pathway, the dopaminergic system, and the Wnt signaling pathway. (4) Conclusions: The novel ceRNA network related to RA that we constructed offers novel insights into and targets for the underlying molecular mechanisms of the mTOR pathway, the dopaminergic system, and the Wnt signaling pathway (both classic and nonclassic pathways) that affect the level of the genetic regulator, which might offer novel ways to treat RA.

In the last decade, new non-apoptotic roles have been ascribed to apoptotic caspases. This family of proteins plays an important role in the sculpting of the brain in the early stages of development by eliminating excessive and nonfunctional synapses and extra cells. Consequently, impairments in this process can underlie many neurological and mental illnesses. This view is particularly relevant to dopamine because it plays a pleiotropic role in motor control, motivation, and reward processing. In this study, we analyze the effects of the elimination of caspase-8 (CASP8) on the development of catecholaminergic neurons using neurochemical, ultrastructural, and behavioral tests. To do this, we selectively delete the CASP8 gene in cells that express tyrosine hydroxylase with the help of recombination through the Cre-loxP system. Our results show that the number of dopaminergic neurons increases in the substantia nigra. In the striatum, the basal extracellular level of dopamine and potassium-evoked dopamine release decreased significantly in mice lacking CASP8, clearly showing the low dopamine functioning in tissues innervated by this neurotransmitter. This view is supported by electron microscopy analysis of striatal synapses. Interestingly, behavioral analysis demonstrates that mice lacking CASP8 show changes reminiscent of autism spectrum disorders (ASD). Our research reactivates the possible role of dopamine transmission in the pathogenesis of ASD and provides a mild model of autism., This work was supported by grants from the Spanish Ministerio de Economía y Competitividad (RTI2018-098645-B-I00), and the Junta de Andalucía (Consejería de Economía y Conocimiento; P18-RT-1372 and US-1264806). JA and EP-V were supported by a MINECO (PID2019-109569GB-I00) grant. IS-P, LB, CL-M, and EB were supported by the “Fondo Europeo de Desarrollo Regional” (FEDER)-UE “A way to build Europe” from the “Ministerio de Economía y Competitividad” (RTI2018-099778-B-I00); from the “Plan Nacional sobre Drogas, Ministerio de Sanidad, Consumo y Bienestar Social” (2019I041); from “Ministerio de Salud-Instituto de Salud Carlos III (PI18/01691); from the “Programa Operativo de Andalucía FEDER, Iniciativa Territorial Integrada ITI 2014-2020 Consejería Salud y Familias, Junta de Andalucía” (PI-0080-2017, PI-0009-2017), "Consejería de Salud y Familias, Junta de Andalucía" (PI-0134-2018 and PEMP-0008-2020); from the "Consejería de Transformación Económica, Industria, Conocimiento y Universidad, Junta de Andalucía" (P20_00958 and CTS-510); from the CEIMAR (CEIJ-003); from the “Instituto de Investigación e Innovación en Ciencias Biomédicas de Cádiz-INiBICA” (LI19/06IN-CO22; IN-C09); from the “CIBERSAM” (CB07/09/0033) and from the European Union’s Horizon 2020 research and innovation programme under the Marie Sklodowska-Curie grant agreement No 955684. Images were obtained in the Centro de Investigación, Tecnología e Innovación de la Universidad de Sevilla (CITIUS).

Ankyrin repeat and kinase domain containing 1 (ANKK1) is a member of the receptor-interacting protein serine/threonine kinase family, known to be involved in cell proliferation, differentiation and activation of transcription factors. Genetic variation within the ANKK1 locus is suggested to play a role in vulnerability to addictions. However, ANKK1 mechanism of action is still poorly understood. It has been suggested that ANKK1 may affect the development and/or functioning of dopaminergic pathways. To test this hypothesis, we generated a CRISPR-Cas9 loss of function ankk1 zebrafish line causing a 27 bp insertion that disrupts the ankk1 sequence introducing an early stop codon. We found that ankk1 transcript levels were significantly lower in ankk1 mutant (ankk127ins) fish compared to their wild type (ankk1+/+) siblings. In ankk1+/+ adult zebrafish brain, ankk1 protein was detected in isocortex, hippocampus, basolateral amygdala, mesencephalon, and cerebellum, resembling the mammalian distribution pattern. In contrast, ankk1 protein was reduced in the brain of ankk127ins/27ins fish. Quantitative polymerase chain reaction analysis revealed an increase in expression of drd2b mRNA in ankk127ins at both larval and adult stages. In ankk1+/+ adult zebrafish brain, drd2 protein was detected in cerebral cortex, cerebellum, hippocampus, and caudate homolog regions, resembling the pattern in humans. In contrast, drd2 expression was reduced in cortical regions of ankk127ins/27ins being predominantly found in the hindbrain. No differences in the number of cell bodies or axonal projections detected by anti-tyrosine hydroxylase immunostaining on 3 days post fertilization (dpf) larvae were found. Behavioral analysis revealed altered sensitivity to effects of both amisulpride and apomorphine on locomotion and startle habituation, consistent with a broad loss of both pre and post synaptic receptors. Ankk127ins mutants showed reduced sensitivity to the effect of the selective dopamine receptor antagonist amisulpride on locomotor responses to acoustic startle and were differentially sensitive to the effects of the non-selective dopamine agonist apomorphine on both locomotion and habituation. Taken together, our findings strengthen the hypothesis of a functional relationship between ANKK1 and DRD2, supporting a role for ANKK1 in the maintenance and/or functioning of dopaminergic pathways. Further work is needed to disentangle ANKK1’s role at different developmental stages.

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES Fundação de Amparo à Pesquisa do Estado do Rio Grande do Sul - FAPERGS Amphetamine (AMPH) addiction is a chronic and relapsing disease caused by the compulsive drug seeking and continued use despite harmful consequences. Currently, there is no effective and approved pharmacological treatment for the treatment of this important neuropsychiatric condition. Thus, the search for new therapeutic targets that can favor the treatment of drug addiction and reduce recurrent relapses represents the biggest challenge for the cure of the condition. Cannabidiol (CBD) has shown many benefits in the treatment of diseases that affect the central nervous system and recently, it has been considered a potential strategy for the treatment of addiction.Thus, the present study aimed to evaluate the effects of CBD on neurochemical and behavioral parameters of relapse in rats AMPH-exposed, whose execution involved two experimental protocols. In experimental protocol 1 (EP1), the effects of CBD treatment on behavioral parameters of relapse after conditioning and reconditioning with AMPH after drug preference extinction were evaluated. In that protocol, animals were initially exposed to ANF (4 mg/kg, i.p) in the conditioned place preference (CPP) protocol for 8 days. After the CPP test, the animals received CBD treatment (5 or 10 mg/kg, i.p) during the 5 days of drug abstinence. Subsequently, the animals were exposed again to AMPH (reconditioning) for 3 days and the relapse test was performed. In experimental protocol 2 (EP2), the aim was to investigate the effects of CBD treatment on behavioral parameters of relapse to AMPH induced by a stressor stimulus. For this, the animals were exposed to AMPH(4 mg/kg, i.p) through the CPP protocol for 8 days and sequentially treated with CBD (10 mg/kg, i.p) during the 5 days of drug abstinence. Relapse drug-seeking behavior was induced by a forced swimming protocol prior to relapse testing. In both protocols, the animals were also submitted to behavioral assessments in the open field test and elevated plus maze to analyze locomotor activity and anxiety behaviors, respectively. Furthermore, in PE1, the prefrontal cortex (PFC) and ventral striatum (EV) were collected for the analysis of dopaminergic targets through western blot, while in PE2, the regions chosen were the ventral tegmental area (VTA) and the EV for the analysis of dopaminergic and endocannabinoid targets. Our results showed that, in both experimental protocols, CBD prevented AMPH relapse and decreased anxiety behavior per se, also observed in animals exposed to AMPH. In EP1, CBD restored the levels of dopaminergic targets (D1R, D2R, DAT and TH), altered by AMPH exposure in both brain regions.This same effect of CBD on D1R, D2R and DAT in VE was observed in EP2. Molecular analysis of EP2 also revealed that in VTA, CBD restored CB1R levels lowered by AMPH exposure, increased levels of the enzyme responsible for endocannabinoid synthesis, NAPE-PLD, and decreased levels of the enzyme that degrades them, the FAAH. These molecular findings allow us to hypothesize that the potential anti-relapse effect of CBD reflects its ability to increase endocannabinoid tone and thus restore the dopaminergic system compromised by AMPH exposure. Although further studies are needed, CBD appears to be a promising pharmacological alternative for the treatment of addiction to psychostimulant drugs such as AMPH. A adição à anfetamina (ANF) é uma doença crônica e recidivante caracterizada pela busca e uso compulsivo da droga, apesar de suas consequências prejudiciais. Atualmente, não há tratamento farmacológico eficaz e aprovado para o tratamento dessa importante condição neuropsiquiátrica. Deste modo, a busca por novos alvos terapêuticos que possam favorecer o tratamento da drogadição e reduzir as recorrentes recaídas representa o maior desafio para a cura da condição. O canabidiol (CBD) tem mostrado muitos benefícios no tratamento de doenças que afetam o sistema nervoso central e recentemente, tem sido considerado uma potencial estratégia para o tratamento da adição. Assim, o presente estudo teve por objetivo avaliar os efeitos do CBD sobre parâmetros neuroquímicos e comportamentais de recaída em ratos expostos à ANF, cuja execução envolveu dois protocolos experimentais. No protocolo experimental 1 (PE1), os efeitos do tratamento com CBD sobre parâmetros comportamentais de recaída após condicionamento e recondicionamento com ANF depois da extinção da preferência pela droga foram avaliados. Nesse protocolo, os animais foram inicialmente expostos à ANF (4 mg/kg, i.p) no protocolo de preferência condicionada de lugar (PCL) por 8 dias. Após o teste de PCL, os animais receberam tratamento com CBD (5 ou 10 mg/kg, i.p) durante os 5 dias de abstinência à droga. Na sequência, os animais foram expostos novamente à ANF (recondicionamento) por 3 dias e o teste de recaída foi executado. No protocolo experimental 2 (PE2), o objetivo foi investigar os efeitos do tratamento com CBD sobre parâmetros comportamentais de recaída à ANF induzida por um estímulo estressor. Para isto, os animais foram expostos à ANF (4 mg/kg, i.p) através do protocolo de PCL por 8 dias e sequencialmente tratados com CBD (10 mg/kg, i.p) durante os 5 dias de abstinência da droga. O comportamento de recaída à busca pela droga foi induzido por um protocolo de nado forçado antes do teste de recaída. Em ambos protocolos, os animais também foram submetidos a avaliações comportamentais no teste de campo aberto e labirinto em cruz elevado para análise da atividade locomotora e comportamentos de ansiedade, respectivamente. Além disso, no PE1, o córtex pré-frontal (CPF) e o estriado ventral (EV) foram coletados para a análise de alvos dopaminérgicos através de western blot, enquanto que no PE2, as regiões escolhidas foram a área tegmental ventral (ATV) e o EV para a análise de alvos dopaminérgicos e endocanabinoides. Nossos resultados mostraram que, em ambos os protocolos experimentais, o CBD preveniu a recaída à ANF e diminuiu o comportamento de ansiedade per se, também observado nos animais expostos à ANF. No PE1, o CBD restaurou os níveis dos alvos dopaminérgicos (D1R, D2R, DAT e TH), alterados pela exposição à ANF em ambas as regiões cerebrais. Esse mesmo efeito do CDB sobre D1R, D2R e DAT no EV foi observado no PE2. As análises moleculares do PE2 também revelaram que na ATV, o CBD restaurou os níveis de CB1R diminuídos pela exposição à ANF, aumentou os níveis da enzima responsável pela síntese dos endocanabinoides, a NAPE-PLD, e diminuiu os níveis da enzima que faz a degradação destes, a FAAH. Esses achados moleculares nos permitem hipotetizar que o potencial efeito anti-recaída do CBD reflete a capacidade deste em aumentar o tônus endocanabinoide e, então, restaurar o sistema dopaminérgico comprometido pela exposição à ANF. Embora estudos adicionais sejam necessários, o CBD mostra-se como uma alternativa farmacológica promissora para o tratamento da adição por drogas psicoestimulantes como a ANF.

Background: The pathogenesis of dystonia is remarkably diverse. Some types of dystonia, such as DYT5 (DYT-GCH1) and tardive dystonia, are related to dysfunction of the dopaminergic system. Furthermore, on pathological examination, cell loss in the substantia nigra (SN) of patients with dystonia has been reported, suggesting that impaired dopamine production may be involved in DYT5 and in other types of dystonia.Objectives: To investigate functional dopaminergic impairments, we compared patients with dystonia and those with Parkinson's disease (PD) with normal controls using neuromelanin-sensitive magnetic resonance imaging (NM-MRI) and dopamine transporter single photon emission computed tomography (DAT SPECT).Methods: A total of 18, 18, and 27 patients with generalized or segmental dystonia, patients with PD, and healthy controls, respectively, were examined using NM-MRI. The mean area corresponding to NM in the SN (NM-SN) was blindly quantified. DAT SPECT was performed on 17 and eight patients with dystonia and PD, respectively. The imaging data of DAT SPECT were harmonized with the Japanese database using striatum phantom calibration. These imaging data were compared between patients with dystonia or PD and controls from the Japanese database in 256 healthy volunteers using the calibrated specific binding ratio (cSBR). The symptoms of dystonia were evaluated using the Fahn–Marsden Dystonia Rating Scale (FMDRS), and the correlation between the results of imaging data and FMDRS was examined.Results: The mean areas corresponding to NM in the SN (NM-SN) were 31 ± 4.2, 28 ± 3.8, and 43 ± 3.8 pixels in patients with dystonia, PD, and in healthy controls, respectively. The mean cSBRs were 5 ± 0.2, 2.8 ± 0.2, 9.2 (predictive) in patients with dystonia, PD, and in healthy controls, respectively. The NM-SN area (r = −0.49, p < 0.05) and the cSBR (r = −0.54, p < 0.05) were inversely correlated with the FMDRS. There was no significant difference between the dystonia and PD groups regarding NM-SN (p = 0.28). In contrast, the cSBR was lower in patients with PD than in those with dystonia (p < 0.5 × 10−6).Conclusions: Impairments of the dopaminergic system may be involved in developing generalized and segmental dystonia. SN abnormalities in patients with dystonia were supposed to be different from degeneration in PD.

The dopaminergic system (DS) is one of the most important neuromodulator systems involved in complex functions that are compromised in both autism spectrum disorder (ASD) and attention deficit/hyperactivity disorder (ADHD), conditions that frequently occur in overlap. This evidence suggests that both disorders might have common neurobiological pathways involving the DS. Therefore, the aim of this study was to examine the DRD1 and DRD2 dopamine receptor single nucleotide polymorphisms (SNPs) as potential risk factors for ASD, ADHD, and ASD/ADHD overlap. Genetic data were obtained from four groups: 75 ASD patients, 75 ADHD patients, 30 patients with ASD/ADHD overlap, and 75 healthy controls. All participants were between 2 and 17 years old. We compared the genotypic and allelic frequency of 18 SNPs among all of the study groups. Moreover, in the case of statistically significant differences, odds ratios (OR) were obtained to evaluate if the presence of SNPs might be a risk factor of developing a specific clinical phenotype. This study found that DRD1 and DRD2 receptors SNPs might be considered as potential risk factors for ASD and ADHD. However, only DRD2-12 (rs7131465) was significantly associated with a higher risk for the ASD/ADHD overlap. These data support the hypothesis of the genetic neuromodulation of the DS in the neurobiology of these conditions.

Previous neuroimaging studies have suggested that the neural bases of trait emotional intelligence (TEI) lie in the social cognition network (SCN) and the somatic marker circuitry (SMC). The current study was the first to investigate the associations of total TEI factors and subfactors with mean diffusivity (MD) of these networks as well as regional MD of the dopaminergic system (MDDS). We found that TEI intrapersonal factor score and total TEI score were negatively correlated with regional MDDS in the vicinity of the right putamen and right pallidum and that TEI intrapersonal factor score was negatively correlated with MD values of the fusiform gyrus. Total TEI score and TEI factor scores were positively correlated with MD values of various areas within or adjacent to SCN components, SMC structures and the lateral prefrontal cortex (LPFC). Our MD findings demonstrated the importance of the dopaminergic system to TEI and implicate the SCN, SMC and LPFC in TEI. Future studies are required to investigate the implications of positive and negative associations with MD values.

Despite the high prevalence of medicinal use and abuse of opioids, their neurobiology and mechanisms of action are not fully understood. Experimental (animal) models are critical for improving our understanding of opioid effects in vivo. As zebrafish (Danio rerio) are increasingly utilized as a powerful model organism in neuroscience research, mounting evidence suggests these fish as a useful tool to study opioid neurobiology. Here, we discuss the zebrafish opioid system with specific focus on opioid gene expression, existing genetic models, as well as its pharmacological and developmental regulation. As many human brain diseases involve pain and aberrant reward, we also summarize zebrafish models relevant to opioid regulation of pain and addiction, including evidence of functional interplay between the opioid system and central dopaminergic and other neurotransmitter mechanisms. Additionally, we critically evaluate the limitations of zebrafish models for translational opioid research and emphasize their developing utility for improving our understanding of evolutionarily conserved mechanisms of pain-related, addictive, affective and other behaviors, as well as for fostering opioid-related drug discovery. (C) 2019 IBRO. Published by Elsevier Ltd. All rights reserved.

Despite the high prevalence of medicinal use and abuse of opioids, their neurobiology and mechanisms of action are not fully understood. Experimental (animal) models are critical for improving our understanding of opioid effects in vivo. As zebrafish (Danio rerio) are increasingly utilized as a powerful model organism in neuroscience research, mounting evidence suggests these fish as a useful tool to study opioid neurobiology. Here, we discuss the zebrafish opioid system with specific focus on opioid gene expression, existing genetic models, as well as its pharmacological and developmental regulation. As many human brain diseases involve pain and aberrant reward, we also summarize zebrafish models relevant to opioid regulation of pain and addiction, including evidence of functional interplay between the opioid system and central dopaminergic and other neurotransmitter mechanisms. Additionally, we critically evaluate the limitations of zebrafish models for translational opioid research and emphasize their developing utility for improving our understanding of evolutionarily conserved mechanisms of pain-related, addictive, affective and other behaviors, as well as for fostering opioid-related drug discovery. (C) 2019 IBRO. Published by Elsevier Ltd. All rights reserved.

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES Psychotic disorders, as schizophrenia and substance-induced psychoses (amphetamine, for example), are characterized by the appearance of delusions, hallucinations and other, and their symptoms are associated with hyperactivation of the mesolimbic dopaminergic pathway. Antipsychotics antagonize D2-type dopamine (DA) receptors in this pathway and due to it, they have been used for the treatment of psychotic symptoms. Herbal medicines have also been used as alternatives to the treatment of symptoms of central nervous system (CNS) disorders. Piper methysticum (P. methysticum), named Kava Kava, fits in this context because it has action on GABAergic and dopaminergic receptors, on the enzyme monoamine oxidase (MAO) and others. Research in animal models, such as in Caenorhabditis elegans (C. elegans) and rodents, has been carried out to better understand the symptoms, pharmacological treatment and its mechanisms, as well as the use of possible adjuvants to the pharmacological therapy of psychotic disorders. Thus, the first main of this study was to investigate the effects of the antipsychotic haloperidol on the dopaminergic system in C. elegans. The animals were exposed to haloperidol (80 or 160 μM) for 1-6 days and behavioral, molecular and morphological assays were performed. Haloperidol increased survival, decreased locomotor behavior and DA levels in these animals, but it did not alter neither dop-1, dop-2 and dop-3 genes expression, nor the morphology of cephalic dopaminergic neurons. Moreover, locomotion speed recovered to basal conditions upon haloperidol withdrawal. Haloperidol’s effects on C. elegans seem to be related to modulation of the D2-type DA receptor. Regarding the herbal medicine Kava Kava, the crude extract was used to investigate its effects in an animal model of psychosis-like symptoms induced by amphetamine on behavioral changes and on MAO activity. Mice received Kava extract (40 mg/Kg) or vehicle (corn oil) by gavage; 2 h later, amphetamine (1.25 mg/kg) or vehicle (0.9% NaCl) by an intraperitoneal injection. 25 min later, behavioral tests showed that Kava extract exhibited anxiolytic effect in the elevated plus-maze test, increased the locomotor activity in the open-field test and decreased MAO-A activity in the cortex and MAO-B activity in the hippocampus of the animals. Kava extract prevented the effects of amphetamine on stereotyped behavior and, the co-treatment increased the number of entries into arms in Y maze test as well as MAO-B activity in striatum of mice. However, the hyperlocomotion induced by amphetamine was not altered by previous treatment with the extract. The social interaction was not modified for the treatment. The results showed that Kava extract avoided the increase of stereotyped behavior induced by amphetamine in mice, which could be investigated as a possible adjuvant in the pharmacological therapy to minimize psychotic symptoms in patients. Lastly, the third main of this study investigated the effect of Kava extract (10-400 mg/kg, by gavage) on MAO activity in different mouse brain structures and on behavioral changes after 21 days of treatment as well as, in in vitro assays (10-100 μg/ml of the extract) in mouse brain homogenate. Kava extract increased the percentage of entries into the open arms in the plus-maze test and decreased MAO-B activity in the cortex (10 mg/kg) and in the region containing the substantia nigra (10 and 100 mg/kg) in assays ex vivo. In vitro, Kava extract reversibly inhibited MAO-B activity with IC50 of 14.62 μg/mL, increased Km values (10, 30 μg/ml) and decreased Vmax (100 μg/ml). Thus, the extract showed different effects on MAO-B isoform depending on the brain structure evaluated, which could be promissory in pathologies where MAO-B is the pharmacological target. The totality of results presented in this thesis revealed useful results conditioned to psychosis, information which becomes relevant for future studies related to this disorder. Transtornos psicóticos, como a esquizofrenia e as psicoses induzidas por substâncias de uso abusivo (por exemplo, anfetamina), são caracterizados pelo aparecimento de delírios, alucinações, entre outros e, seus sintomas estão associados à hiperativação da via dopaminérgica mesolímbica. Os antipsicóticos antagonizam os receptores de dopamina (DA) do tipo D2 nesta via e por isso são utilizados para o tratamento dos sintomas psicóticos. Os fitoterápicos também vêm sendo utilizados como alternativas ao tratamento de sintomas decorrentes de patologias do sistema nervoso central (SNC). Piper methysticum (P. methysticum), popularmente chamado de Kava Kava, se enquadra neste contexto pois possui ação em receptores gabaérgicos, dopaminérgicos, sobre a enzima monoaminoxidase (MAO), entre outros. Pesquisas em modelos animais, como em Caenorhabditis elegans (C. elegans) e roedores, vêm sendo realizadas para melhor compreender os sintomas, tratamento farmacológico e seus mecanismos, bem como a utilização de possíveis adjuvantes à terapia farmacológica dos transtornos psicóticos. Desta forma, o primeiro objetivo deste estudo foi investigar os efeitos do antipsicótico haloperidol no sistema dopaminérgico em C. elegans. Os animais foram expostos ao haloperidol (80 ou 160 μM) durante 1-6 dias e, avaliações comportamentais, moleculares e morfológicas foram realizadas. O haloperidol aumentou a sobrevivência, diminui o comportamento locomotor e os níveis de DA nesses animais, mas não alterou a expressão dos genes dop-1, dop-2 e dop-3 nem a morfologia dos neurônios dopaminérgicos cefálicos. Após a retirada do fármaco, o comportamento locomotor retornou a níveis de atividade basal. Os efeitos do haloperidol em C. elegans parecem estar associados a modulação de receptores do tipo D2 de DA. Em relação ao fitoterápico Kava Kava, o extrato bruto foi utilizado para investigar os seus efeitos em um modelo animal de psicose induzido por anfetamina sobre alterações comportamentais e na atividade da enzima MAO. Camundongos receberam por gavagem o extrato de Kava (40 mg/Kg) ou veículo (óleo de milho); 2 h após, anfetamina (1,25 mg/Kg) ou veículo (NaCl 0,9%) pela via intraperitoneal. 25 min depois, testes comportamentais mostraram que o extrato de Kava causou efeito ansiolítico no teste de labirinto em cruz elevado, aumentou a atividade locomotora no teste de campo aberto e diminui a atividade da MAO-A no córtex e da MAO-B no hipocampo dos animais. O extrato evitou os efeitos da anfetamina no comportamento estereotipado e o co-tratamento aumentou o número de entradas nos braços no teste de labirinto em Y e na atividade da MAO-B no estriado de camundongos. Entretanto, a hiperlocomoção induzida pela anfetamina não foi alterada pelo tratamento prévio com o extrato. A interação social não foi modificada. Os resultados mostram que o extrato de Kava preveniu o aparecimento do comportamento estereotipado induzido por anfetamina em camundongos, o qual poderia ser investigado como um possível adjuvante à terapia farmacológica para minimizar sintomas psicóticos em pacientes. Por fim, o terceiro objetivo deste estudo investigou o efeito do extrato de Kava (10-400 mg/kg, administrado por gavagem) sobre a atividade da MAO em diferentes estruturas do cérebro de camundongos e sobre alterações comportamentais após 21 dias de tratamento, bem como, em ensaios in vitro (10-100 μg/mL do extrato) utilizando homogeneizado de cérebro de camundongos. O extrato de Kava aumentou o percentual de entradas nos braços abertos do labirinto em cruz elevado e diminuiu a atividade da MAO-B no córtex (10 mg/Kg) e na região contendo a substância negra (10 e 100 mg/Kg) em ensaios ex vivo. In vitro, o extrato de Kava inibiu reversivelmente a atividade da MAO-B com IC50 de 14,62 μg/mL, aumentou os valores de Km (10, 30 μg/mL) e diminuiu a Vmax (100 μg/mL). Assim, o extrato apresentou diferentes efeitos sobre a MAO-B dependendo da estrutura cerebral avaliada, o qual pode ser promissor em patologias onde a MAO-B esteja envolvida. A totalidade de resultados apresentados nesta tese revelaram resultados úteis e condicionadas a psicose, informações as quais tornam-se relevantes para estudos futuros relacionados a este transtorno.

The elderly population is growing worldwide, with important health and socioeconomic implications. Clinical and experimental studies on aging have uncovered numerous changes in the brain, such as decreased neurogenesis, increased synaptic defects, greater metabolic stress, and enhanced inflammation. These changes are associated with cognitive decline and neurobehavioral deficits. Although aging is not a disease, it is a significant risk factor for functional worsening, affective impairment, disease exaggeration, dementia, and general disease susceptibility. Conversely, life events related to mental stress and trauma can also lead to accelerated age-associated disorders and dementia. Here, we review human studies and studies on mice and rats, such as those modeling human neurodegenerative diseases, that have helped elucidate (1) the dynamics and mechanisms underlying the biological and pathological aging of the main projecting systems in the brain (glutamatergic, cholinergic, and dopaminergic) and (2) the effect of defective glutamatergic, cholinergic, and dopaminergic projection on disabilities associated with aging and neurodegenerative disorders, such as Alzheimer’s and Parkinson’s diseases. Detailed knowledge of the mechanisms of age-related diseases can be an important element in the development of effective ways of treatment. In this context, we briefly analyze which adverse changes associated with neurodegenerative diseases in the cholinergic, glutaminergic and dopaminergic systems could be targeted by therapeutic strategies developed as a result of our better understanding of these damaging mechanisms.

Among the animal models of Parkinson’s disease (PD), the 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-lesioned mouse model has shown both dopaminergic (DA) damage and related motor control defects, as observed in patients with PD. Recent studies have suggested that the DA system interacts with the synaptic plasticity of the hippocampus in PD. However, little is known about how alterations in the hippocampal structural plasticity are affected by the DA damage in MPTP-lesioned models. In the present study, we investigated alterations in dendritic complexity and spine density in the mouse hippocampus following acute MPTP treatment (22 mg/kg, intraperitoneally, four times/day, 2-h intervals). We confirmed that acute MPTP treatment significantly decreased initial motor function and persistently reduced the number of tyrosine hydroxylase-positive DA neurons in the substantia nigra. Golgi staining showed that acute MPTP treatment significantly reduced the spine density of neuronal dendrites in the cornu ammonis 1 (CA1) apical/basal and dentate gyrus (DG) subregions of the mouse hippocampus at 8 and 16 days after treatment, although it did not affect dendritic complexity (e.g., number of crossing dendrites, total dendritic length, and branch points per neuron) in both CA1 and DG subregions at all time points after treatment. Therefore, the present study provides anatomical evidence that acute MPTP treatment affects synaptic structure in the hippocampus during the late phase after acute MPTP treatment in mice, independent of any changes in the dendritic arborization of hippocampal neurons. These findings offer data for the ability of the acute MPTP-lesioned mouse model to replicate the non-nigrostriatal lesions of clinical PD.

Although it is known that health is not merely the absence of disease, the positive aspects of mental health have been less comprehensively researched compared with its negative aspects. Subjective well-being is one of the indicators of positive psychology, and high subjective well-being is considered to benefit individuals in multiple ways. However, the neural mechanisms underlying individual differences in subjective well-being remain unclear, particularly in terms of brain microstructural properties as detected by diffusion tensor imaging. The present study aimed to investigate the relationship between measurements of diffusion tensor imaging (mean diffusivity and fractional anisotropy) and the degree of subjective well-being as measured using a questionnaire. Voxel-based analysis was used to investigate the association between mean diffusivity and subjective well-being scores in healthy young adults (age, 20.7 ± 1.8 years; 695 males and 514 females). Higher levels of subjective well-being were found to be associated with lower mean diffusivity in areas surrounding the right putamen, insula, globus pallidus, thalamus, and caudate. These results indicated that individual subjective well-being is associated with variability in brain microstructural properties.

Transtornos neuropsiqui?tricos s?o doen?as incapacitantes que atingem um n?mero significativo de pessoas. Suas bases biol?gicas n?o s?o completamente compreendidas, mas sabe-se que altera??es em sistemas de neurotransmiss?o desempenham importante papel na sua patog?nese. Os sistemas dopamin?rgico e purin?rgico est?o envolvidos em in?meras fun??es cerebrais e s?o associados a muitos transtornos. Agentes farmacol?gicos que interagem com sistemas de neurotransmiss?o permitem investigar respostas celulares e moleculares mediadas por estes, podendo elucidar a fisiopatologia de tais transtornos. O quinpirole, agonista dopamin?rgico dos receptores D2/D3, permite o estudo de mecanismos subjacentes a dist?rbios neuropsiqui?tricos, atrav?s de modelos animais. O peixezebra ? amplamente utilizado na pesquisa biom?dica translacional e empregado com sucesso em estudos psicofarmacol?gicos. Neste estudo, tr?s protocolos de administra??o de quinpirole foram realizados em peixe-zebra e avalia??es comportamentais, morfol?gicas e bioqu?micas foram estudadas. A exposi??o larval (6 dias p?s-fertiliza??o, dpf) ao quinpirole (5,5, 16,7, 50 ?M) por 1h induziu hiperatividade, comportamento do tipo ansioso, movimentos err?ticos e repetitivos e prejudicou respostas optomotoras. Os efeitos observados foram dependentes do estado nutricional, apenas animais alimentados apresentaram altera??es comportamentais. Peixes-zebra adultos (6 meses) receberam duas inje??es intraperitoneais de quinpirole com intervalo de 48h (0,5, 1,0, 2,0 mg/kg), e exibiram hipolocomo??o, comportamento do tipo ansioso, movimentos err?ticos e estereotipados e comprometimento de mem?ria. Quinpirole induziu aumento dos n?veis do fator neurotr?fico derivado do c?rebro e glutamato e diminui??o de serotonina. No terceiro protocolo, a exposi??o ao quinpirole por 24h (5,5, 16,7, 50 ?M) aos 5 dpf causou altera??es tardias. Aos 120 dpf, animais expostos apresentaram comportamento do tipo ansioso, movimentos err?ticos e estereotipados e comprometimento de mem?ria. A atividade enzim?tica das ectonucleotidases, adenosina desaminase (ADA) e metabolismo de ATP foram avaliados. Para larvas, o quinpirole alterou a atividade das nucleos?deo trifosfato difosfoidrolases (NTPDases), diminuindo a hidr?lise de ADP, e induziu aumento dos n?veis de ATP, AMP, ADO e INO. Em animais adultos, diminui??o da hidr?lise de ADP e desamina??o de adenosina foi observado, indicando altera??o das NTPDases e ADA. Al?m disso, foi observado aumento de ADP e diminui??o de AMP, ADO e INO. A an?lise aos 120 dpf ap?s a exposi??o ao quinpirole na fase larval n?o alterou a atividade enzim?tica. Entretanto, uma diminui??o dos n?veis dos nucleot?deos e nucleos?deos avaliados foi observada. Em resumo, as altera??es comportamentais observadas compreendem o espectro comportamental de diversos transtornos neuropsiqui?tricos. Ainda, os resultados com larvas indicam que as altera??es comportamentais observadas dependem do estado nutricional - consumo de alimento, um est?mulo naturalmente recompensador relacionado ao sistema dopamin?rgico, tornou os receptores mais suscet?veis ao quinpirole. O protocolo em peixes-zebra adultos demonstrou, al?m das altera??es comportamentais, modifica??es neuropl?sticas no sistema nervoso central do peixe-zebra. Al?m disso, altera??es comportamentais tardias foram observadas ap?s exposi??o ao quinpirole na fase larval. Ainda, foi observado que o quinpirole pode inibir as atividades das NTPDases e ADA, modulando n?veis de nucleot?deos e nucleos?deos, indicando o envolvimento da sinaliza??o purin?rgica em dist?rbios neurol?gicos. Assim, o presente estudo demonstra que a exposi??o ao quinpirole em peixe-zebra pode ser uma ferramenta apropriada para an?lise de mecanismos subjacentes aos transtornos neuropsiqui?tricos. Neuropsychiatric disorders are disabling diseases that affect a significant number of people. Although its biological basis is not fully understood, it is known that changes in neurotransmission systems play an important role in its pathogenesis. The dopaminergic and purinergic systems are involved in numerous brain functions, and are associated with many disorders. Pharmacological agents that interact with the neurotransmission systems allow investigating cellular and molecular responses mediated by them, which may elucidate the patophysiology of such disorders. Quinpirole, a dopamine D2/D3 receptor agonist, allows the study of mechanisms underlying neuropsychiatric disorders, using animal models. The zebrafish is widely used in translational biomedical research and has been successfully used in psychopharmacology studies. In the present study, three quinpirole administration protocols were performed in zebrafish and behavioral, morphological and biochemical analysis were performed. Quinpirole exposure (5.5, 16.7, 50 ?M) during 1h in larvae (6 days post-fertilization, dpf) induced hyperactivity, anxiety-like behavior, erratic and repetitive movements, and impair optomotor responses. The effects observed were dependent upon feeding status, only fed animals showed behavioral alterations. Adult zebrafish (6 months) received two intraperitoneal injections of quinpirole with an inter-injection interval of 48h (0.5, 1.0, 2.0 mg/kg), and exhibited hypolocomotion, anxiety-like behavior, erratic and stereotypic movements, and memory impairment. The quinpirole treatment induced increased brain neurotrophic factor and glutamate levels, and decreased levels of serotonin. In the third protocol, exposure to quinpirole during 24h (5.5, 16.7, 50 ?M) at 5 dpf led to late alterations. At 120 dpf, animals exposed to quinpirole exhibited anxiety-like behavior, erratic and stereotypic movements, and impaired memory. The enzymatic activity of ectonucleotidases, adenosine deaminase (ADA) and the ATP metabolism were evaluated. For larvae, quinpirole altered the nucleoside triphosphate diphosphohydrolase (NTPDase) activities by promoting a decrease in ADP hydrolysis, and induced increased ATP, AMP, ADO and INO levels. In adults, decrease in ADP hydrolysis and adenosine deamination was observed, indicating alterations on NTPDase and ADA activities. Additionally, increased ADP and decreased AMP, ADO and INO levels were observed. The analysis performed at 120 dpf after quinpirole exposure during development had no alterations on enzymatic activity. However, decreased levels for the nucleotide and nucleosides evaluated were observed. In summary, the behavioral alterations observed are part of the behavioral spectrum of several neuropsychiatric disorders. Furthermore, the results with larvae indicate that the behavioral effects of quinpirole exposure are depended upon feeding status ? food intake, a naturally rewarding stimulus known to engage the dopaminergic system, became the receptors more susceptible to quinpirole?s effects. The protocol in adult zebrafish showed that more than behavioral alterations, quinpirole administration led to neuroplastic changes in the central nervous system of zebrafish. Furthermore, the third protocol showed that quinpirole exposure can lead to late behavioral alterations. Last, the findings of this study demonstrated that quinpirole administration may inhibit NTPDases and ADA activities, modulating nucleotide and nucleoside levels, indicating the involvement of purinergic signaling on neurological disorders. Thus, the present study shows that the use of quinpirole exposure may be an appropriate tool for the analysis of mechanics underlying neuropsychiatric disorders. Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior - CAPES

Trans-regulation of G protein-coupled receptors (GPCRs) by leucine-rich repeat (LRR) transmembrane proteins has emerged as a novel type of synaptic molecular interaction in the last decade. Several studies on LRR–GPCR interactions have revealed their critical role in synapse formation and in establishing synaptic properties. Among them, LRR–GPCR interactions between extracellular LRR fibronectin domain-containing family proteins (Elfn1 and Elfn2) and metabotropic glutamate receptors (mGluRs) are particularly interesting as they can affect a broad range of synapses through the modulation of signaling by glutamate, the principal excitatory transmitter in the mammalian central nervous system (CNS). Elfn–mGluR interactions have been investigated in hippocampal, cortical, and retinal synapses. Postsynaptic Elfn1 in the hippocampus and cerebral cortex mediates the tonic regulation of excitatory input onto somatostatin-positive interneurons (INs) through recruitment of presynaptic mGluR7. In the retina, presynaptic Elfn1 binds to mGluR6 and is necessary for synapse formation between rod photoreceptor cells and rod-bipolar cells. The repertoire of binding partners for Elfn1 and Elfn2 includes all group III mGluRs (mGluR4, mGluR6, mGluR7, and mGluR8), and both Elfn1 and Elfn2 can alter mGluR-mediated signaling through trans-interaction. Importantly, both preclinical and clinical studies have provided support for the involvement of the Elfn1–mGluR7 interaction in attention-deficit hyperactivity disorder (ADHD), post-traumatic stress disorder (PTSD), and epilepsy. In fact, Elfn1–mGluR7-associated disorders may reflect the altered function of somatostatin-positive interneuron inhibitory neural circuits, the mesolimbic and nigrostriatal dopaminergic pathway, and habenular circuits, highlighting the need for further investigation into this interaction., Frontiers in Neural Circuits, 15, art. no. 634875; 2021

This book provides a comprehensive overview of the use of PET and SPECT in the classic psychiatric disorders such as depression, bipolar disorder, anxiety disorders, and schizophrenia. In addition, it discusses the application of these functional neuroimaging techniques in a variety of other conditions, including sleep disorders, eating disorders, autism, and chronic fatigue syndrome. The new edition has been extensively revised and updated to reflect the latest advances and results in nuclear imaging within the field. Most chapters are written jointly by a clinical psychiatrist and a nuclear medicine expert to ensure a multidisciplinary approach. This state of the art compendium will be of value for all who have an interest in the field of neuroscience, from psychiatrists and radiologists/nuclear medicine specialists to interested general practitioners and cognitive psychologists. Companion volumes on the use of PET and SPECT in neurology and for the imaging of neurobiological systems complete a trilogy.

The normal functioning of dopaminergic system is compromised during Alzheimer’s disease (AD). The activity of monoamine oxidase B (MAOB), enzyme involved in degradation of dopamine, is also disturbed in AD. It was observed that MAOB activity is increased during AD. Also, increased expression of MAOB was detected in hippocampus and cortex of people who suffered from AD. It was observed that MAOB rs1799836 polymorphism can affect MAOB transcription, consequently influencing also protein translation and MAOB activity. Our recent study showed that the levels of cerebrospinal fluid amyloid β1-42 were decreased in patients carrying A allele in MAOB rs1799836 polymorphism. The goal of this study was to compare MAOB rs1799836 polymorphism with APOE, the only confirmed genetic risk factor for sporadic AD. Study included 253 participants of whom 127 suffered from AD, 57 were mild cognitive impairment patients, 11 were healthy controls and 58 suffered from other primary causes of dementia. We observed that the number of APOE ɛ4/ɛ4 homozygotes and APOE ɛ4 carriers was significantly increased among patients carrying AA MAOB rs1799836 genotype. These results indicate that the MAOB rs1799836 polymorphism could be strong genetic biomarker of AD. Acknowledgements: Supported by The Croatian Science Foundation grant IP-2019-04-3584 (“Role of blood-brain barrier, innate immunity, and tau protein oligomerization in the pathogenesis of Alzheimer's disease”) to GŠ and by the Centre of Excellence for Basic, Clinical and Translational Neuroscience CoRE-NEURO (“Experimental and clinical research of hypoxic- ischemic damage in perinatal and adult brain” ; GA KK01.1.1.01.0007 funded by the European Union through the European Regional Development Fund)

Introduction. Parkinson’s disease (PD) is characterized by a progressive loss of dopaminergic neurons followed by neuroinflammation. While chronic treatments with dopamine replacement drugs such as L-DOPA are effective in ameliorating the symptoms of PD, such treatments are associated with complications such as dyskinesia. A non-dopaminergic treatment targeting adenosine A2A receptors could be promising for the treatment of motor fluctuations and underlying neuroinflammatory processes. Methods. Rats bearing unilateral intra-striatal 6-hydroxydopamine lesions were treated chronically [20 days] with vehicle [n=8] or KW6002 [3mg/kg, n=8]. Rats were scanned (60-min dynamic) on days 7,8 and 21,22 post-surgery with [11C]PBR28 and [11C]raclopride to measure neuroinflammation and D2R availability respectively. A peak in neuroinflammation was observed with [11C]PBR28-PET on day 7, thus, on that day, 16 other rats were sacrificed for post-mortem analysis. [11C]PBR28 uptake was calculated as a SUVRatio [ipsilateral/contralateral] whereas [11C]raclopride binding potential [BPND] was calculated via SRTM2 , using cerebellum as a reference. BPND values in left and right striatum were calculated from [11C]raclopride scans. Post-mortem analyses were used to quantify microglia (Iba-1 immunofluorescence) and dopaminergic loss (tyrosine hydroxylase [TH] western blot). Motor and asymmetric paw use were evaluated by rotarod and cylinder tests. The generalized estimated equation (GEE) model was applied to longitudinal datasets (PET, behavioral tests), and the independent samples t-test to post-mortem studies. Significance was measured at pResults: Chronic KW6002 treatment significantly decreased the [11C]PBR28 SUVRatio compared with vehicle [vehicle=1.59±0.26, KW6002=1.26±0.06 on day 7; p=0.001 vehicle=1.35±0.21, KW6002=1.19±0.08 on day 21; p=0.045]. KW6002 also significantly decreased the BPND of [11C]raclopride in the left and right-striatum compared with vehicle (vehicle1.80±0.17 and 1.73±0.124; KW6002=1.56±0.194 and 1.50±0.201 on day 8, p=0.03 and 0.049 respectively; vehicle=1.83±0.28 and 1.72±0.24, KW6002=1.56±0.25 and 1.43±0.26 on day 22, p=0.03 and 0.014 respectively]. An 84% increase of DAPI+/Iba-1+ cells was observed in right-striatum [relative to left-striatum] of vehicle-treated compared to KW6002-treated rats on day 22 [p-value=0.007]. Preliminary results of TH immunoblot suggested smaller dopaminergic loss in left -striatum of KW6002 animals compared with vehicle on day 7[p=0.010]. KW6002 caused a significant improvement in rotarod performance [pConclusion: The reduced [11C]PBR28 uptake ratio and reduced number of Iba-1+ cells indicate amelioration of neuroinflammation. Reduced [11C]raclopride binding and improved TH levels indicate improved dopamine synthesis. Thus, KW6002 improves the motor symptoms of PD by reducing dopaminergic neuron loss and enhancing dopaminergic functions.

This book provides a comprehensive overview of the use of PET and SPECT in the classic psychiatric disorders such as depression, bipolar disorder, anxiety disorders, and schizophrenia. In addition, it discusses the application of these functional neuroimaging techniques in a variety of other conditions, including sleep disorders, eating disorders, autism, and chronic fatigue syndrome. The new edition has been extensively revised and updated to reflect the latest advances and results in nuclear imaging within the field. Most chapters are written jointly by a clinical psychiatrist and a nuclear medicine expert to ensure a multidisciplinary approach. This state of the art compendium will be of value for all who have an interest in the field of neuroscience, from psychiatrists and radiologists/nuclear medicine specialists to interested general practitioners and cognitive psychologists. Companion volumes on the use of PET and SPECT in neurology and for the imaging of neurobiological systems complete a trilogy.

This book provides a comprehensive overview of the use of PET and SPECT in the classic psychiatric disorders such as depression, bipolar disorder, anxiety disorders, and schizophrenia. In addition, it discusses the application of these functional neuroimaging techniques in a variety of other conditions, including sleep disorders, eating disorders, autism, and chronic fatigue syndrome. The new edition has been extensively revised and updated to reflect the latest advances and results in nuclear imaging within the field. Most chapters are written jointly by a clinical psychiatrist and a nuclear medicine expert to ensure a multidisciplinary approach. This state of the art compendium will be of value for all who have an interest in the field of neuroscience, from psychiatrists and radiologists/nuclear medicine specialists to interested general practitioners and cognitive psychologists. Companion volumes on the use of PET and SPECT in neurology and for the imaging of neurobiological systems complete a trilogy.

Background: Recent cross-sectional studies highlighted the loss of dopaminergic neurons in the ventral tegmental area (VTA) as an early pathophysiological event in Alzheimer’s disease (AD). \ud \ud Objective: In this study, we longitudinally investigated by resting-state fMRI (RS-fMRI) a cohort of patients with mild cognitive impairment (MCI) due to AD to evaluate the impact of VTA disconnection in predicting the conversion to AD. \ud \ud Methods: a cohort of 35 patients with MCI due to AD were recruited and followed-up for 24 months. They underwent cognitive evaluation and RS-fMRI to assess VTA connectivity at baseline and at follow-up. \ud \ud Results: At 24-month follow-up, 16 out of 35 patients converted to AD. Although converters and non-converters to AD did not differ in demographic and behavioral characteristics at baseline, the first group showed a significant reduction of VTA-driven connectivity in the posterior cingulate and precentral cortex. This pattern of additional disconnection in MCI-converters compared to non-converters remained substantially unchanged at 24-month follow-up. \ud \ud Discussion: This study reinforces the hypothesis of an early contribution of dopaminergic dysfunction to AD evolution by targeting the default-mode network. These results have potential implications for AD staging and prognosis and support new opportunities for therapeutic interventions to slow down disease progression

Medical imaging techniques like PET and SPECT have been applied for investigation of brain function in anorexia and bulimia nervosa. Regional abnormalities have been detected in cerebral blood flow, glucose metabolism, the availability of several neurotransmitter receptors (serotonin 1A and 2A, dopamine D2/D3, histamine H1, mu-opioid, GABA(A)-benzodiazepine, and cannabinoid CB1), stimulant-induced dopamine release, presynaptic FDOPA influx, and the density of serotonin transporters. Different subtypes of eating disorders appear to be associated with specific functional changes. It is hard to judge whether such changes are a consequence of chronic dietary restrictions or are caused by a putative anorexia (or bulimia) nervosa endophenotype. Many abnormalities (particularly those of glucose metabolism) appear to be reversible after restoration of weight or normal patterns of food intake and may represent consequences of purging or starvation. However, some changes of regional flow and neurotransmitter systems persist even after successful therapy which suggests that these reflect traits that are independent of the state of the illness. Changes of the serotonergic system (altered activity of 5-HT1A and 5-HT2A receptors and 5-HT transporters) may contribute to dysregulation of appetite, mood, and impulse control in eating disorders and may represent a trait which predisposes to the development of anxiety, obsessionality, and behavioral inhibition. Assessment of functional changes in the brain with PET or SPECT may have prognostic value and predict neuropsychological status after several years of therapy.

Introduction. Parkinson’s disease (PD) is characterized by a progressive loss of dopaminergic neurons followed by neuroinflammation. While chronic treatments with dopamine replacement drugs such as L-DOPA are effective in ameliorating the symptoms of PD, such treatments are associated with complications such as dyskinesia. A non-dopaminergic treatment targeting adenosine A2A receptors could be promising for the treatment of motor fluctuations and underlying neuroinflammatory processes. Methods. Rats bearing unilateral intra-striatal 6-hydroxydopamine lesions were treated chronically [20 days] with vehicle [n=8] or KW6002 [3mg/kg, n=8]. Rats were scanned (60-min dynamic) on days 7,8 and 21,22 post-surgery with [11C]PBR28 and [11C]raclopride to measure neuroinflammation and D2R availability respectively. A peak in neuroinflammation was observed with [11C]PBR28-PET on day 7, thus, on that day, 16 other rats were sacrificed for post-mortem analysis. [11C]PBR28 uptake was calculated as a SUVRatio [ipsilateral/contralateral] whereas [11C]raclopride binding potential [BPND] was calculated via SRTM2 , using cerebellum as a reference. BPND values in left and right striatum were calculated from [11C]raclopride scans. Post-mortem analyses were used to quantify microglia (Iba-1 immunofluorescence) and dopaminergic loss (tyrosine hydroxylase [TH] western blot). Motor and asymmetric paw use were evaluated by rotarod and cylinder tests. The generalized estimated equation (GEE) model was applied to longitudinal datasets (PET, behavioral tests), and the independent samples t-test to post-mortem studies. Significance was measured at p

The kidney is critical in the long-term regulation of blood pressure. Oxidative stress is one of the many factors that is accountable for the development of hypertension. The five dopamine receptor subtypes (D1R–D5R) have important roles in the regulation of blood pressure through several mechanisms, such as inhibition of oxidative stress. Dopamine receptors, including those expressed in the kidney, reduce oxidative stress by inhibiting the expression or action of receptors that increase oxidative stress. In addition, dopamine receptors stimulate the expression or action of receptors that decrease oxidative stress. This article examines the importance and relationship between the renal dopaminergic system and oxidative stress in the regulation of renal sodium handling and blood pressure. It discusses the current information on renal dopamine receptor-mediated antioxidative network, which includes the production of reactive oxygen species and abnormalities of renal dopamine receptors. Recognizing the mechanisms by which renal dopamine receptors regulate oxidative stress and their degree of influence on the pathogenesis of hypertension would further advance the understanding of the pathophysiology of hypertension.

The initiation of an addiction involves the dopamine system (DA), and particularly the ventral tegmental area (VTA) which contributes to the processing of reinforcement learning. Drugs hijack these functions, leading to an overvaluation of the drug reward at the expense of natural rewards. Nicotine, the main addictive compound of tobacco, exerts its reinforcing effects through its action on nicotinic acetylcholine receptors, in turn increasing the activity of DA neurons in the VTA and DA release in downstream targets. My thesis work addresses the issue of variability in VTA DA neuron responses to nicotine, and behavioral changes associated with its chronic use. The first part aimed, by combining in vivo electrophysiology in anesthetized mice and retrograde tracing, to characterize a sub-population of DA neurons inhibited by nicotine injection. I thus demonstrated that the two subpopulations of DA neurons characterized by their activation or inhibition in response to nicotine have distinct projection sites, and respectively mediate reinforcing and aversive effects of the drug. The second part of my work focused on the neurophysiological bases underlying co-morbidities between nicotine addiction and associated pathological behavioral manifestations, proposing DA as a common substrate. I showed that increased DA neuron activity following chronic nicotine exposure causes perturbations in choice behavior in mice, likely by increasing sensitivity to reward value., Le système dopaminergique (DA) de l’aire tegmentale ventrale (VTA) est fortement impliqué dans les apprentissages par renforcement et dans l'initiation de la consommation de drogues d’abus. Ces dernières détournent ces fonctions d’apprentissage, de telle sorte que les effets positifs des drogues sont surévalués aux dépends des récompenses naturelles. La nicotine, principal composé addictif du tabac, exerce ses effets renforçants par son action sur les récepteurs nicotiniques de l'acétylcholine. En s’y liant, elle augmente l’activité des neurones DA, et entraîne une libération DA accrue dans la VTA et ses structures cibles. Mon travail de thèse adresse la question de la variabilité des réponses DA induites par une injection de nicotine et des changements comportementaux associés à son usage chronique. La première partie a visé, en combinant électrophysiologie in vivo et traçage de voies, à caractériser une sous-population de neurones DA inhibés par une injection de nicotine. J'ai ainsi démontré que deux sous-populations de neurones DA répondant respectivement par une activation ou une inhibition à la nicotine ont des sites de projection distincts, et médient des effets renforçants et aversifs. La seconde partie de mon travail porte sur les bases neurophysiologiques qui sous-tendent les comorbidités entre l’addiction à la nicotine et les manifestations pathologiques associées, en proposant la dopamine comme substrat commun. On démontre que l’augmentation d’activité des neurones DA après une exposition chronique à la nicotine provoquerait des perturbations dans le comportement de choix chez la souris, et une sensibilité accrue à la valeur de récompense.

Improving exercise capacity during adolescence impacts positively on cognitive and motor functions. However, the neural mechanisms contributing to enhance physical performance during this sensitive period remain poorly understood. Such knowledge could help to optimize exercise programs and promote a healthy physical and cognitive development in youth athletes. The central dopamine system is of great interest because of its role in regulating motor behavior through the activation of D1 and D2 receptors. Thus, the aim of the present study is to determine whether D1 or D2 receptor signaling contributes to modulate the exercise capacity during adolescence and if this modulation takes place through the striatum. To test this, we used a rodent model of forced running wheel that we implemented recently to assess the exercise capacity. Briefly, rats were exposed to an 8-day period of habituation in the running wheel before assessing their locomotor performance in response to an incremental exercise test, in which the speed was gradually increased until exhaustion. We found that systemic administration of D1-like (SCH23390) and/or D2-like (raclopride) receptor antagonists prior to the incremental test reduced the duration of forced running in a dose-dependent manner. Similarly, locomotor activity in the open field was decreased by the dopamine antagonists. Interestingly, this was not the case following intrastriatal infusion of an effective dose of SCH23390, which decreased motor performance during the incremental test without disrupting the behavioral response in the open field. Surprisingly, intrastriatal delivery of raclopride failed to impact the duration of forced running. Altogether, these results indicate that the level of locomotor response to incremental loads of forced running in adolescent rats is dopamine dependent and mechanistically linked to the activation of striatal D1 and extra-striatal D2 receptors.

Dnmt3a2, a de novo DNA methyltransferase, is induced by neuronal activity and participates in long-term memory formation with the increased expression of synaptic plasticity genes. We wanted to determine if Dnmt3a2 with its partner Dnmt3L may influence motor behavior via the dopaminergic system. To this end, we generated a mouse line, Dnmt3a2/3LDat/wt, with dopamine transporter (DAT) promotor driven Dnmt3a2/3L overexpression. The mice were studied with behavioral paradigms (e.g., cylinder test, open field, and treadmill), brain slice patch clamp recordings, ex vivo metabolite analysis, and in vivo positron emission tomography (PET) using the dopaminergic tracer 6-[18F]FMT. The results showed that spontaneous activity and exercise performance were enhanced in Dnmt3a2/3LDat/wt mice compared to Dnmt3a2/3Lwt/wt controls. Dopaminergic substantia nigra pars compacta neurons of Dnmt3a2/3LDat/wt animals displayed a higher fire frequency and excitability. However, dopamine concentration was not increased in the striatum, and dopamine metabolite concentration was even significantly decreased. Striatal 6-[18F]FMT uptake, reflecting aromatic L-amino acid decarboxylase activity, was the same in Dnmt3a2/3LDat/wt mice and controls. [18F]FDG PET showed that hypothalamic metabolic activity was tightly linked to motor behavior in Dnmt3a2/3LDat/wt mice. Furthermore, dopamine biosynthesis and motor-related metabolic activity were correlated in the hypothalamus. Our findings suggest that Dnmt3a2/3L, when overexpressed in dopaminergic neurons, modulates motor performance via activation of the nigrostriatal pathway. This does not involve increased dopamine synthesis.

The activity of dopamine (DA)-containing neurons in the ventral tegmental area (VTA) is a key mechanism in mesolimbic reward processing that has modulatory effects on different diencephalic structures like hippocampus (HIP), and receives inhibitory feedback and excitatory feed forward control. In addition, within the hippocampus, DA receptors are mostly located in the dorsal part (CA1) and dopaminergic innervations are predominant in this sub-region. The current study aimed to examine the effect of intra-hippocampal CA1 administration of SCH23390 and Sulpiride as D1- and D2-like receptor antagonists on the acquisition of orexin-induced conditioned place preference (CPP), respectively. Cannulas were unilaterally implanted into the VTA and HIP of adult male albino Wistar rats weighing 200-250 g. For induction of CPP, orexin A (10 ng/0.3 µL saline) was daily microinjected into the VTA during a three-day conditioning phase. Thereafter, various doses of SCH23390 and Sulpiride (0.25, 1 and 4 µg) were unilaterally injected into the CA1 during this 3-day conditioning phase after intra-VTA administration. The conditioning score was then calculated. Results revealed that intra-CA1 administration of D1- and D2-like receptor antagonists during the 3-day conditioning phase attenuated the acquisition of place preference by orexin A in a dose-dependent manner. It seems the effect of D2-like receptor antagonist within the CA1 region of hippocampus on this phenomenon was found to be more considerable than that of D1-like receptor antagonist. It is concluded that orexin-induced CPP may be mediated, at least in part, by stimulation of DA receptors in the CA1.

Cocaine use disorder and methamphetamine use disorder are chronic, relapsing disorders with no US Food and Drug Administration-approved interventions. Repetitive transcranial magnetic stimulation (rTMS) is a non-invasive brain stimulation tool that has been increasingly investigated as a possible therapeutic intervention for substance use disorders. rTMS may have the ability to induce beneficial neuroplasticity in abnormal circuits and networks in individuals with addiction. The aim of this review is to highlight the rationale and potential for rTMS to treat cocaine and methamphetamine dependence: we synthesize the outcomes of studies in healthy humans and animal models to identify and understand the neurobiological mechanisms of rTMS that seem most involved in addiction, focusing on the dopaminergic and glutamatergic systems. rTMS-induced changes to neurotransmitter systems include alterations to striatal dopamine release and metabolite levels, as well as to glutamate transporter and receptor expression, which may be relevant for ameliorating the aberrant plasticity observed in individuals with substance use disorders. We also discuss the clinical studies that have used rTMS in humans with cocaine and methamphetamine use disorders. Many such studies suggest changes in network connectivity following acute rTMS, which may underpin reduced craving following chronic rTMS. We suggest several possible future directions for research relating to the therapeutic potential of rTMS in addiction that would help fill current gaps in the literature. Such research would apply rTMS to animal models of addiction, developing a translational pipeline that would guide evidence-based rTMS treatment of cocaine and methamphetamine use disorder.

Adverse early life events are a well-established risk factor for the precipitation of behavioral disorders characterized by anomalies in the dopaminergic system, such as schizophrenia and addiction. The correlation between early life conditions and the dopaminergic system has been causally investigated in more than 90 rodent publications. Here, we tested the validity of the hypothesis that early life stress (ELS) alters dopamine signaling by performing an extensive 3-level mixed effect meta-analysis. We included several ELS models and biochemical indicators of the dopaminergic system in a variety of brain areas, for a total of 1009 comparisons. Contrary to our expectations, only a few comparisons displayed a significant effect. Specifically, the striatal area was the most vulnerable, displaying decreased dopamine precursor and increased metabolites after ELS. To make all data openly accessible, we created MaDEapp (https://osf.io/w25m4/), a tool to explore data of the meta-analysis with the intent to guide future (pre)clinical research and allow power calculations. All in all, ELS induces a few yet robust changes on biochemical indicators of the dopaminergic system.

The Basolateral Amygdala (BLA) has modulatory effects on working and reference memory. The aim of this study was the evaluation of effects of dopaminergic system in the BLA of rats on working and reference memory behaviors. The number of working and reference errors and time spent in the arms by rats were measured in the radial arm maze according to DSWS protocol. The animals were cannulated in the BLA bilaterally. The microinjection of low dose (0.005µg/rat) and high dose (0.5 µg/rat) of apomorphine have indicated a significant decrease in number of working memory error. But, there was not any change in the numberof reference memory error that showing the improvement of working memory. While the injection of moderate dose apomorphine (0.05 µg/rat) increased these parameters and also enhanced the spent time in working arm that presenting both memories damage. The chlorpromazine injection (2 µg/rat) decreased the number of working and reference memory errors representing the improvement of these memories. Microinjection of chlorpromazine (2 µg/rat) with different doses of apomorphine had no significant change on the both number of errors and the time spent in comparison with control groups. These findings show that BLA dopaminergic system modulates the working and reference memory through that both of (D1/D2) receptors. Also, the effect of this system in BLA is the resultant function of the both receptor families.

Background The mean diffusivity (MD) parameter obtained by diffusion tensor imaging provides a measure of how freely water molecules move in brain tissue. Greater tissue density conferred by closely arrayed cellular structures is assumed to lower MD by inhibiting the free diffusion of water molecules. Methods In this paper, we review studies showing MD variation among regions of the brain dopaminergic system (MDDS), especially subcortical structures such as the putamen, caudate nucleus, and globus pallidus, in different conditions with known associations to dopaminergic system function or dysfunction. The methodologies and background related to MD and MDDS are also discussed. Results Past studies indicate that MDDS is sensitive to pathological derangement of dopaminergic activity, neural changes caused by cognitive and pharmacological interventions that are known to affect the dopaminergic system, and individual character traits related to dopaminergic function. Conclusion These results suggest that MDDS can be one useful tool to tap the neural differences related to the dopaminergic system.

Fibromyalgia (FM) is a complex pathology described as persistent hyperalgesia including somatic and mood dysfunctions, depression and anxiety. Although the etiology of FM is still unknown, a significant decrease in biogenic amines is a common characteristic in its pathogenesis. Here, our main objective was to investigate the role of dopamine D3/D2 receptor during the reserpine-induced pain in mice. Our results showed that pramipexole (PPX) – a dopaminergic D3/D2 receptor agonist – inhibited mechanical allodynia and thermal sensitivity induced by reserpine. Relevantly, PPX treatment decreased immobility time and increased the number of grooming in the forced swimming test and splash test, respectively. Animals that received PPX remained longer in the open arms than the reserpine group using elevated plus-maze apparatus. The repeated PPX administration, given daily for 4 days, significantly blocked the mechanical and thermal allodynia during FM model, similarly to pregabalin, although it failed to affect the reserpine-induced thermal nociception. Reserpine administration induced significant downregulation of dopamine concentration in the central nervous system, and repeated treatment with PPX restored dopamine levels in the frontal cortex and spinal cord tissues. Moreover, PPX treatment inhibited oxidants production such as DCFH (2′,7′-dichlorodihydrofluorescein) and nitrite, also decreased oxidative damage (carbonyl), and upregulated the activity of superoxide dismutase in the spinal cord. Together, our findings demonstrated the ability of dopamine D3/D2 receptor-preferring agonist in reducing pain and mood dysfunction allied to FM in mice. All experimental protocols were approved by the Universidade Federal de Santa Catarina (UFSC) Ethics Committee (approval No. 2572210218) on May 10, 2018.

Methylmercury (MeHg) is a ubiquitous pollutant shown to cause developmental neurotoxicity, even at low levels. However, there is still a large gap in our understanding of the mechanisms linking early-life exposure to life-long behavioural impairments. Our aim was to characterise the short- and long-term effects of developmental exposure to low doses of MeHg on anxiety-related behaviours in zebrafish, and to test the involvement of neurological pathways related to stress-response. Zebrafish embryos were exposed to sub-acute doses of MeHg (0, 5, 10, 15, 30 nM) throughout embryo-development, and tested for anxiety-related behaviours and locomotor activity at larval (light/dark locomotor activity) and adult (novel tank and tap assays) life-stages. Exposure to all doses of MeHg caused increased anxiety-related responses, heightened response to the transition from light to dark in larvae, and a stronger dive response in adults. In addition, impairment in locomotor activity was observed in the higher doses in both larvae and adults. Finally, the expressions of several neural stress-response genes from the HPI-axis and dopaminergic system were found to be disrupted in both life-stages. Our results provide important insights into dose-dependent differences in exposure outcomes, the development of delayed effects over the life-time of exposed individuals and the potential mechanisms underlying these effects.

Dopamine (DA) is produced and released by immune cells. Recent data pointed to DA as a key mediator between the nervous and immune systems. In the present study we tested the hypothesis that peripheral dopaminergic system plays a negative role in ulcerative colitis pathogenesis via the effect on activity of peripheral blood phagocytes. The study was conducted on male Wistar rats (170-200 g). The peripheral dopaminergic system was destroyed by 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) injection (20 mg/kg, s.c., 4 times every 2 h). Colitis was induced by 0.1 ml 6% iodoacetamide enema. Rats were subjected to autopsy on the 18th day. We found that MPTP-treated rats had decreased levels of tyrosine hydroxylase, rate-limiting enzyme of DA synthesis, in colon but not in brain. The number and activity of colonic and peripheral blood granulocytes did not significantly differ in saline- and MPTP-treated rats with colitis. The decreased ROS production by monocytes; increased 1.8-fold the number of CD69 (an early activation marker) positive monocytes and 6-fold intensity of CD69 surface expression were observed in MPTP-treated rats vs. saline-treated rats during colitis. The CD14 (the endotoxin coreceptor of phagocytes) surface expression was 2-fold increased in MPTP-treated rats without colitis, but significantly decreased in both saline- and MPTP-treated rats with colitis. We showed for the first time that the destruction of peripheral dopaminergic neurons leads to the improvement of morphological signs of experimental colitis, which might be through the regulatory effect of dopaminergic system on monocytes phenotype and their respiratory burst activity.

Midbrain dopaminergic neurons are implicated in the control of motor functions and reward-driven behaviours. The function of this neuronal population is strongly connected with distinct patterns of firing - irregular or bursting, which either maintains basal levels of dopamine (DA) or leads to phasic release, respectively. Heterogeneity of dopaminergic neurons, observed on both structural and functional levels, is also reflected in different responses of DA neurons to changes in global brain states. Preparation of urethane anaesthetized animal is a broadly used model to study brain state dependent activity of neurons. Unfortunately activity of midbrain DA neurons across urethane induced cyclic, spontaneous brain state alternations is poorly described. To fulfil this gap in our knowledge we have performed simultaneous, extracellular recordings of the firing of single putative DA neurons combined with continuous brain state monitoring. We found that during slow wave activity, the firing rate of recorded putative DA neurons was significantly higher compared to firing rates during activated state, both in ventral tegmental area (VTA) and substantia nigra pars compacta (SNc). In the presence of cortical slow waves, putative dopaminergic neurons also intensified bursting activity, but the magnitude of this phenomena differed in respect to the examined region (VTA or SNc). Our results show that activity of DA neurons under urethane anaesthesia is brain-state dependent and emphasize the importance of brain state monitoring during electrophysiological experiments.

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No. of bitstreams: 1 anselmo_f_dr_bot_par.pdf: 701284 bytes, checksum: b2a4834c27927f793b26b0183ed09bd9 (MD5) Previous issue date: 2020-02-20 Approved for entry into archive by ROSANGELA APARECIDA LOBO null (rosangelalobo@btu.unesp.br) on 2020-04-15T20:23:13Z (GMT) No. of bitstreams: 1 anselmo_f_dr_bot_par.pdf: 701284 bytes, checksum: b2a4834c27927f793b26b0183ed09bd9 (MD5) Approved for entry into archive by ROSANGELA APARECIDA LOBO null (rosangelalobo@btu.unesp.br) on 2020-04-15T20:23:13Z (GMT) No. of bitstreams: 1 anselmo_f_dr_bot_par.pdf: 701284 bytes, checksum: b2a4834c27927f793b26b0183ed09bd9 (MD5) Made available in DSpace on 2020-04-15T20:23:13Z (GMT). No. of bitstreams: 1 anselmo_f_dr_bot_par.pdf: 701284 bytes, checksum: b2a4834c27927f793b26b0183ed09bd9 (MD5) Previous issue date: 2020-02-20 Made available in DSpace on 2020-04-15T20:23:13Z (GMT). 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No. of bitstreams: 1 anselmo_f_dr_bot_par.pdf: 701284 bytes, checksum: b2a4834c27927f793b26b0183ed09bd9 (MD5) Previous issue date: 2020-02-20 Approved for entry into archive by ROSANGELA APARECIDA LOBO null (rosangelalobo@btu.unesp.br) on 2020-04-15T20:23:13Z (GMT) No. of bitstreams: 1 anselmo_f_dr_bot_par.pdf: 701284 bytes, checksum: b2a4834c27927f793b26b0183ed09bd9 (MD5) Submitted by FÁBIO ANSELMO null (anselmof_unesp@yahoo.com.br) on 2020-04-13T13:09:01Z No. of bitstreams: 1 Fábio Anselmo - Tese com ficha cat..pdf: 964195 bytes, checksum: d1223e9628a4c9b1d11c88ba4f7e7aa3 (MD5) Approved for entry into archive by ROSANGELA APARECIDA LOBO null (rosangelalobo@btu.unesp.br) on 2020-04-15T20:23:13Z (GMT) No. of bitstreams: 1 anselmo_f_dr_bot_par.pdf: 701284 bytes, checksum: b2a4834c27927f793b26b0183ed09bd9 (MD5) Made available in DSpace on 2020-04-15T20:23:13Z (GMT). No. of bitstreams: 1 anselmo_f_dr_bot_par.pdf: 701284 bytes, checksum: b2a4834c27927f793b26b0183ed09bd9 (MD5) Previous issue date: 2020-02-20 Made available in DSpace on 2020-04-15T20:23:13Z (GMT). No. of bitstreams: 1 anselmo_f_dr_bot_par.pdf: 701284 bytes, checksum: b2a4834c27927f793b26b0183ed09bd9 (MD5) Previous issue date: 2020-02-20 Made available in DSpace on 2020-04-15T20:23:13Z (GMT). No. of bitstreams: 1 anselmo_f_dr_bot_par.pdf: 701284 bytes, checksum: b2a4834c27927f793b26b0183ed09bd9 (MD5) Previous issue date: 2020-02-20 Approved for entry into archive by ROSANGELA APARECIDA LOBO null (rosangelalobo@btu.unesp.br) on 2020-04-15T20:23:13Z (GMT) No. of bitstreams: 1 anselmo_f_dr_bot_par.pdf: 701284 bytes, checksum: b2a4834c27927f793b26b0183ed09bd9 (MD5) Made available in DSpace on 2020-04-15T20:23:13Z (GMT). No. of bitstreams: 1 anselmo_f_dr_bot_par.pdf: 701284 bytes, checksum: b2a4834c27927f793b26b0183ed09bd9 (MD5) Previous issue date: 2020-02-20 Made available in DSpace on 2020-04-15T20:23:13Z (GMT). No. of bitstreams: 1 anselmo_f_dr_bot_par.pdf: 701284 bytes, checksum: b2a4834c27927f793b26b0183ed09bd9 (MD5) Previous issue date: 2020-02-20 Approved for entry into archive by ROSANGELA APARECIDA LOBO null (rosangelalobo@btu.unesp.br) on 2020-04-15T20:23:13Z (GMT) No. of bitstreams: 1 anselmo_f_dr_bot_par.pdf: 701284 bytes, checksum: b2a4834c27927f793b26b0183ed09bd9 (MD5) Made available in DSpace on 2020-04-15T20:23:13Z (GMT). No. of bitstreams: 1 anselmo_f_dr_bot_par.pdf: 701284 bytes, checksum: b2a4834c27927f793b26b0183ed09bd9 (MD5) Previous issue date: 2020-02-20 Approved for entry into archive by ROSANGELA APARECIDA LOBO null (rosangelalobo@btu.unesp.br) on 2020-04-15T20:23:13Z (GMT) No. of bitstreams: 1 anselmo_f_dr_bot_par.pdf: 701284 bytes, checksum: b2a4834c27927f793b26b0183ed09bd9 (MD5) Made available in DSpace on 2020-04-15T20:23:13Z (GMT). No. of bitstreams: 1 anselmo_f_dr_bot_par.pdf: 701284 bytes, checksum: b2a4834c27927f793b26b0183ed09bd9 (MD5) Previous issue date: 2020-02-20 Made available in DSpace on 2020-04-15T20:23:13Z (GMT). No. of bitstreams: 1 anselmo_f_dr_bot_par.pdf: 701284 bytes, checksum: b2a4834c27927f793b26b0183ed09bd9 (MD5) Previous issue date: 2020-02-20 Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) O herbicida atrazina (ATR) é um praguicida usado intensivamente na agricultura, que persiste no meio ambiente e causa toxicidade em espécies não-alvo, inclusive seres humanos. Considerando o potencial da ATR para produzir efeitos no sistema nervoso central (SNC) e a falta de informações na literatura corrente sobre esse tipo de toxicidade, o objetivo deste projeto de pesquisa foi avaliar os efeitos da exposição subcrônica ao herbicida ATR sobre parâmetros neurocomportamentais específicos e estabelecer sua correlação com o estresse oxidativo (EO) em tecido cerebral de ratos e com o sistema dopaminérgico em regiões específicas do cérebro, nominalmente córtex pré-frontal (CPF), hipocampo (HIP) e corpo estriado. Ratos Wistar machos receberam solução salina (0,3 ml; controle - Ct), atrazina (ATR; 100 mg/kg), atrazina mais vitamin E (ATR; 100 mg/Kg + VE; 200 mg/kg), apenas vitamina E (VE; 200 mg/kg), atrazina mais levodopa (ATR; 100 mg/Kg + LEV; 20 mg/kg) e apenas levodopa (LEV; 20 mg/kg), por gavage, durante 28 dias. O comportamento foi avaliado utilizando arena de campo aberto (ACA), labirinto em cruz elevado (LCE) e hole-board (HB). O teste de estresse oxidativo no tecido cerebral avaliou os níveis de malondialdeído (MDA), capacidade antioxidante hidrofílica (CAH) e atividade das enzimas superóxido dismutase (SOD) e catalase (CAT). A dopamina (DA) foi quantificada por HPLC, em áreas cerebrais específicas (CPF, HIP e estriado). Exposição à ATR provocou ansiedade, diminuiu a coordenação motora e não alterou a atividade locomotora dos animais. A ATR não modificou os níveis de MDA, a CAH nem as atividades da SOD e CAT. No entanto, ATR+VE aumentou os níveis de MDA e a CAH enquanto a VE aumentou a atividade da SOD. Além disso, o tratamento com ATR não alterou os níveis de DA no estriado cerebral, mas aumentou sua concentração no CPF e no HIP. Como conclusão, observou-se que a exposição subcrônica ao herbicida ATR foi capaz de prejudicar parâmetros comportamentais específicos, principalmente aqueles relacionados a ansiedade e a coordenação motora. Esses prejuízos não estão relacionados com a indução de EO no tecido cerebral de ratos. Além disso, sugere-se atenção em situações de suplementação oral por VE, pois, quando combinada com substâncias do tipo praguicidas, pode exercer efeitos pró-oxidantes a nível de SNC. Adicionalmente a ATR foi capaz de causar perturbações nos sistemas dopaminérgicos cerebrais de ratos, principalmente nas regiões do CPF e HIP, não alterando os níveis de DA na região do estriado. Esses resultados reforçam a relação entre exposição à praguicidas e efeitos de neurotoxicidade. Atrazine (ATR) herbicide is a pesticide used intensively in agriculture that persists in environment and causes toxicity on non-target species, include humans. Considering the potential of ATR to produce effects on the central nervous system (CNS) and the lack of information in the current literature about this type of toxicity, the aim of this research project was to evaluate the effects of subchronic exposure to ATR herbicide on specific neurobehavioral parameters and to establish its correlation with oxidative stress (OE) in rat brain tissue and with the dopaminergic system in specific brain regions, nominally prefrontal cortex (PFC), hippocampus (HIP) and striatum. Male Wistar rats received saline (0.3 ml; control - Ct), atrazine (ATR; 100 mg/kg), atrazine plus vitamin E (ATR; 100 mg/Kg + VE; 200 mg/kg) only vitamin E (VE; 200 mg/kg), atrazine plus levodopa (ATR; 100 mg/Kg + LEV; 20 mg/kg) and only levodopa (LEV; 20 mg/kg), via gavage, during 28 days. Behavior was assessed using open field arena (OF), elevated plus-maze (EPM) and hole-board (HB) apparatus. Oxidative stress assay in brain tissue evaluated malondialdehyde (MDA) levels, hydrophilic antioxidant capacity (HAC), and superoxide dismutase (SOD) and catalase (CAT) enzymes activity. Dopamine (DA) was quantified using HPLC, in specific brain areas (PFC, HIP and striatum). ATR exposure caused anxiety-like behavior, decreased motor coordination and did not alter the locomotor activity of the animals. ATR did not change the MDA levels, the HAC, or SOD and CAT activities. However, ATR+VE increased MDA levels and the HAC while VE increased SOD activity. Additionally, ATR treatment did not change DA levels in the striatum cerebral, but increased its concentration in PFC and HIP. As a conclusion, it was observed that subchronic exposure to ATR herbicide was able to impair specific behavioral parameters, especially those related to anxiety and motor coordination. These impairs are not related to OE induction in brain tissue of the rats. Moreover, attention is suggested in situations of oral VE supplementation, because, when combined with substances like pesticides, it can exert pro-oxidant effects in the CNS. Additionally, ATR was able to cause disturbances in the brain dopaminergic systems of rats, mainly in the regions of PFC and HIP, without altering the DA levels in the striatum region. These results reinforce to relation between pesticides exposure and neurotoxic effects. CAPES: 001

Cushing’s Syndrome (CS), or chronic endogenous hypercortisolism, is a rare and serious disease due to corticotroph pituitary (Cushing’s disease, CD) and extra-pituitary (ectopic CS) tumours overproducing ACTH, or cortisol-secreting adrenal tumours or lesions (adrenal CS). The first-line treatment for CS is represented by the surgical removal of the responsible tumour, but surgery might be unfeasible or ineffective and medical treatment can be required in a relevant percentage of patients with CS, especially CD and ectopic CS. Corticotroph pituitary and extra-pituitary tumours, as well as adrenal tumours and lesions responsible for CS express dopamine receptors (DRs), which have been found to mediate inhibition of hormone secretion and/or cell proliferation in experimental setting, suggesting that dopaminergic system, particularly DRs, might represent a target for the treatment of CS. Dopamine agonists (DAs), particularly cabergoline (CAB), are currently used as off-label treatment for CD, the most common form of CS, demonstrating efficacy in controlling hormone secretion and tumour growth in a relevant number of cases, with the improvement of clinical picture, and displaying good safety profile. Therefore, CAB may be considered a reasonable alternative treatment for persistent or recurrent CD after pituitary surgery failure, but occasionally also before pituitary surgery, as adjuvant treatment, or even instead of pituitary surgery as first-line treatment in case of surgery contraindications or refusal. A certain beneficial effect of CAB has been also reported in ectopic CS. However, the role of DAs in the clinical management of the different types of CS requires further evaluations.

Highlights • Novel data-driven and equation-free analysis for PET data. • Extract spatio-temporal patterns of neurodegeneration. • Decompose disease progression into orthogonal temporal curves., Most neurodegenerative disorders are characterized by progressive loss of neurons throughout the course of disease in the form of specific spatio-temporal patterns. To capture and quantify these coherent patterns across both space and time, traditionally one would either fit a pre-defined model with spatial and temporal parameters or apply analysis in the spatial and temporal domains separately. In this work, we introduce and validate the use of dynamic mode decomposition (DMD), a data-driven multivariate approach, to extract coupled spatio-temporal patterns simultaneously. We apply the method to examine progressive dopaminergic degeneration in 41 patients with Parkinson's disease (PD) using [11C](±)dihydrotetrabenazine (DTBZ) Positron Emission Tomography (PET). DMD decomposed the progressive dopaminergic changes in the putamen into two orthogonal temporal progression curves associated with distinct spatial patterns: 1) an anterior-posterior gradient, the expression of which decreased gradually with disease progression with a higher initial expression in the less affected side; 2) a dorsal-ventral gradient in the less affected side, which was present in early disease stage only. In the caudate, we found a head-tail gradient analogous to the anterior-posterior gradient seen in the putamen; as in the putamen, the expression of this gradient decreased gradually with disease progression with higher expression in the less affected side. Our results with DTBZ PET data show the applicability and relevance of the proposed method for extracting spatio-temporal patterns of neurotransmitter changes due to neurodegeneration. The method is able to decompose known PD-induced dopaminergic denervation into orthogonal (and thus loosely independent) temporal curves, which may be able to reflect and separate either different mechanisms underlying disease progression and disease initiation, or differential involvement of striatal sub-regions at different disease stages, in a completely data driven way. It is expected that this method can be easily extended to other PET tracers and neurodegenerative disorders and may help to elucidate disease mechanisms in more details compared to traditional approaches.

Salidroside, a phenylpropanoid glycoside, is the main bioactive component of Rhodiola rosea L. Salidroside has prominent anti-stroke effects in cerebral ischemia/reperfusion models. However, the underlying mechanisms of its actions are poorly understood. This study examined the anti-stroke effects of salidroside in middle cerebral artery occlusion (MCAO)-induced rat model of stroke and its potential mechanisms involving the dopaminergic system. Salidroside administration increased the levels of dopamine (DA), homovanillic acid (HVA), and 3,4-dihydroxyphenylacetic acid (DOPAC) in the ipsilateral striatum after induction of transient ischemia, which were assessed using microdialysis with high-performance liquid chromatography coupled with electrochemical detection (HPLC-ECD). Furthermore, treatment with salidroside ameliorated neurobehavioral impairment, assessed with the modified neurological severity scores (mNSS), the balance beam test, and the foot fault test. Moreover, enzyme-linked immunosorbent assay (ELISA) suggested that MCAO-induced reduction in monoamine oxidase (MAO) was inhibited by salidroside. Immunohistochemical and immunofluorescence analyses revealed high level of tyrosine hydroxylase (TH) in the ipsilateral striatal caudate putamen (CPu) after cerebral ischemia/reperfusion, which could be further elevated by salidroside. In addition, salidroside could reverse the decreased immunoreactivity of TH in the substantia nigra pars compacta (SNpc). These results suggest that the anti-stroke effects of salidroside in MCAO-induced cerebral ischemia/reperfusion may involve the modulation of monoamine metabolism in the striatum and SNpc, which may be related to the function of the dopaminergic system in the rat brain.

Parkinson's disease (PD) is manifested by progressive motor, autonomic, and cognitive disturbances. Dopamine (DA) synthesizing neurons in the substantia nigra (SN) degenerate, causing a decline in DA level in the striatum that leads to the characteristic movement disorders. A disease-modifying therapy to arrest PD progression remains unattainable with current pharmacotherapies, most of which cause severe side effects and lose their efficacy with time. For this reason, there is a need to seek new therapies supporting the pharmacological treatment of PD. Motor therapy is recommended for pharmacologically treated PD patients as it alleviates the symptoms. Molecular mechanisms behind the beneficial effects of motor therapy are unknown, nor is it known whether such therapy may be neuroprotective in PD patients. Due to obvious limitations, human studies are unlikely to answer these questions; therefore, the use of animal models of PD seems indispensable. Motor therapy in animal models of PD characterized by the loss of dopaminergic neurons has neuroprotective and neuroregenerative effects, and the completeness of neuronal protection may depend on (i) degree of neuronal loss, (ii) duration and intensity of exercise, and (iii) time elapsed between insult and commencing of training. As the physical activity is neuroprotective for dopaminergic neurons, the question arises what is the mechanism of this protective action. A current hypothesis assumes a central role of neurotrophic factors in the neuroprotection of dopaminergic neurons, even though it is still not clear whether increased DA level in the nigrostriatal axis results from neurogenesis of dopaminergic neurons in the SN, recovery of the phenotype of dopaminergic neurons, increased sprouting of the residual dopaminergic axons in the striatum, or generation of local striatal neurons from inhibitory interneurons. In the present review, we discuss studies describing the influence of physical exercise on the PD-like changes manifested in animal models of the disease and focus our interest on the current state of knowledge on the mechanism of neuroprotection induced by physical activity as a supportive therapy in PD.

Salt (sodium chloride) is an essential dietary requirement, but excessive consumption has long-term adverse consequences. A high-salt diet (HSD) increases the risk of chronic diseases such as cardiovascular conditions and diabetes and is also associated with poor sleep quality. Little is known, however, about the neural circuit mechanisms that mediate HSD-induced sleep changes. In this study, we sought to identify the effects of HSD on the sleep and related neural circuit mechanisms of Drosophila. Strikingly, we found that HSD causes young Drosophila to exhibit a fragmented sleep phenotype similar to that of normal aging individuals. Importantly, we further showed that HSD slightly impairs circadian rhythms and that the HSD-induced sleep changes are dependent on the circadian rhythm system. In addition, we demonstrated that HSD-induced sleep changes are dopaminergic-system dependent. Together, these results provide insight into how elevated salt in the diet can affect sleep quality.

The generalization of aversive memory can be defined as the phenomenon in which a situation similar to (but distinctive from) a previous aversive event triggers an avoidance response. This phenomenon has been suggested to play a role in several psychological disorders. In this study, we investigate the effects of novelty on the generalization of fear memories, and the involvement of noradrenergic and dopaminergic systems in this process. For this study we used male Wistar rats (3 months old, 300-400 g). The participation of each neurotransmitter system was evaluated separately (two set of experiments). In each experimental set, the animals were divided in groups (8 animals each): (i) control, (ii) novelty, and, (iii) antagonist + novelty group (timolol, a β-adrenergic antagonist, or SCH23390, a D1/D5 dopaminergic antagonist, in the first and in the second set of experiments, respectively). Additionaly, to investigate whether novelty exposure increases the levels of noradrenaline and/or dopamine in the hippocampus fifteen animals were divided in three groups (5 animals each).: (i) naïve, (ii) control; and, (iii) novelty. To examine aversive memory, and generalization of aversive memory, we trained adult male Wistar rats in an inhibitory avoidance (IA) memory task and after in a modified inhibitory avoidance (MIA). Before the MIA training some of the animals were exposed to environmental novelty (open field). Immediately before this novelty exposure, some animals received intrahippocampal infusion of timolol (β-adrenergic antagonist), SCH23390 (D1/D5 antagonist) or vehicle to evaluate the involvement of noradrenergic and dopaminergic systems. Finally, to evaluate aversive memory and generalization of aversive memory respectively, half of the animals in each group were tested on IA and half on MIA. We confirmed that the exposure to novelty blocks the generalization of aversive memory, but moreover, demonstrated that this process involves activation of β-adrenergic and dopaminergic D1/D5 pathways. We additionally observed that exposure to novelty raises hippocampal levels of noradrenaline and dopamine. This suggests that these neurotransmitters not only influence long-term memory (LTM) as such, but also aversive memory generalization. ispartof: BEHAVIOURAL BRAIN RESEARCH vol:371 ispartof: location:Netherlands status: published

Made available in DSpace on 2019-10-06T16:29:20Z (GMT). No. of bitstreams: 0 Previous issue date: 2019-08-15 Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) The occurrence of pharmaceuticals in the aquatic environment has increased considerably in the last decades, causing negative biochemical, physiological, and behavioral effects in aquatic organisms. In this study, we evaluated the effects of methylphenidate (MPH) on the aggressive behavior, dopamine-related gene transcript levels, monoamine levels, and carboxylesterase transcript levels and activity in the brain of male Nile tilapia (Oreochromis niloticus). Carboxylesterase activity was also measured in the liver and gills. Fish were exposed for 5 days to MPH at 20 and 100 ng L−1. Fish exposed to 100 ng L−1 of MPH showed increased aggressiveness and decreased dopamine (DA) and serotonin (5-HT) levels. No changes were observed in plasma testosterone levels and in the transcript levels of D1 and D2 dopamine receptors, dopamine transporter (DAT), and carboxylesterase 2 (CES2). Exposure to 100 ng L−1 of MPH caused a decrease in the transcript levels of carboxylesterase 3 (CES3) and an increase in tyrosine hydroxylase (TH), while exposure to 20 ng L−1 of MPH increased the transcript levels of D5 dopamine receptor. Carboxylesterase activity was unchanged in the brain and liver and increased in the gills of fish exposed to 20 ng L−1. These results indicate that MPH at 100 ng L−1 increases aggressiveness in Nile tilapia, possibly due to a decrease in 5-HT levels in the brain and alterations in dopamine levels and dopamine-related genes. Department of Chemistry and Environmental Sciences UNESP - Sao Paulo State University Department of Biochemistry UFSC - Federal University of Santa Catarina Department of Physiology UNESP - Sao Paulo State University, Jaboticabal UNIRP - University Center of Rio Preto FACERES - Morphofunctional Laboratory FACERES Medical School Department of Natural Sciences FURB Fundação Universidade Regional de Blumenau Department of Chemistry and Environmental Sciences UNESP - Sao Paulo State University Department of Physiology UNESP - Sao Paulo State University, Jaboticabal CAPES: 001

Copy-number variants of the CYFIP1 gene in humans have been linked to autism spectrum disorders (ASD) and schizophrenia (SCZ), two neuropsychiatric disorders characterized by defects in brain connectivity. Here, we show that CYFIP1 plays an important role in brain functional connectivity and callosal functions. We find that Cyfip1-heterozygous mice have reduced functional connectivity and defects in white matter architecture, similar to phenotypes found in patients with ASD, SCZ and other neuropsychiatric disorders. Cyfip1-deficient mice also present decreased myelination in the callosal axons, altered presynaptic function, and impaired bilateral connectivity. Finally, Cyfip1 deficiency leads to abnormalities in motor coordination, sensorimotor gating and sensory perception, which are also known neuropsychiatric disorder-related symptoms. These results show that Cyfip1 haploinsufficiency compromises brain connectivity and function, which might explain its genetic association to neuropsychiatric disorders., In humans, copy-number variants of the CYFIP1 gene have been associated with autism spectrum disorders and schizophrenia. Here, the authors characterize Cyfip1-heterozygous mice, revealing that they display deficits in brain white matter structure and functional connectivity along with abnormal behaviours.

The co-occurrence of psychotic symptoms and Alzheimer’s disease (AD) is a devastating phenotype that affects around 50% of individuals with AD. We hypothesized that distinct interactions between brain structures and genetic variants in dopaminergic, cholinergic and glutamatergic neurotransmitter systems may be associated with the presence of hallucinations and delusions in AD. Using the Alzheimer’s Disease Neuroimaging Initiative, we identified participants that presented with symptoms of delusions, hallucinations, or both symptoms. PLS-CA was used to identify differences in patterns of interactions between 15 single nucleotide polymorphisms and 82 neuroanatomical regions of interest between AD patients endorsing symptoms of delusions, hallucinations, and matched AD controls. Binary logistic regression analysis was used to cross-validate identified neuroanatomical differences. Results provide preliminary evidence that genetic variants in the glutamatergic system, along with regional brain changes, may uniquely identify those with hallucinations. A trend towards significance was also found which suggests that atrophy to the frontal lobe coupled with preservation of temporal lobe structures may be associated with symptoms of delusions in patients with AD. Overall, results provide evidence of a unique signature of neuroimaging and genetic interactions which may be associated with the presence of different psychotic symptoms in AD.

The term of neurodegenerative diseases covers a heterogeneous group of disorders that are distinguished by progressive degeneration of the structure and function of the nervous system such as dementias, movement disorders, motor neuron disorders, as well as some prion disorders. In recent years, a paradigm shift started for the diagnosis of neurodegenerative diseases, for which successively clinical testing is supplemented by biomarker information. In research scenarios, it was even proposed recently to substitute the current syndromic by a biological definition of Alzheimer’s diseases. PET examinations with various radiotracers play an important role in providing non-invasive biomarkers and co-morbidity information in neurodegeneration. Information on co-morbidity, e.g. Aβ plaques and Lewy-bodies or Aβ plaques in patients with aphasia or the absence of Aβ plaques in clinical AD patients are of interest to expand our knowledge about the pathogenesis of different phenotypically defined neurodegenerative diseases. Moreover, this information is also important in therapeutic trials targeting histopathological abnormalities. The aim of this review is to present an overview of the currently available radiotracers for imaging neurodegenerative diseases in research and in routine clinical settings. In this context, we also provide a short summary of the most frequent neurodegenerative diseases from a nuclear medicine point of view, their clinical and pathophysiological as well as nuclear imaging characteristics, and the resulting need for new radiotracers.