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This article belongs to the Special Issue Involvement of the MAPK Pathway in Cancer and Immunology., The crosstalk between the opioidergic system and mitogen-activated protein kinases (MAPKs) has a critical role in mediating stress-induced behaviors related to the pathophysiology of anxiety. The present study evaluated the basal status and stress-induced alterations of cortico-thalamic MAPKs and other cell fate-related signaling pathways potentially underlying the anxiogenic endophenotype of PDYN gene-deficient mice. Compared to littermates, PDYN knockout (KO) mice had lower cortical and or thalamic amounts of the phospho-activated MAPKs c-Jun N-terminal kinase (JNK1/2) and extracellular signal-regulated kinase (ERK1/2). Similarly, PDYN-KO animals displayed reduced cortico-thalamic densities of total and phosphorylated (at Ser191) species of the cell fate regulator Fas-associated protein with death domain (FADD) without alterations in the Fas receptor. Exposure to acute restraint and chronic mild stress stimuli induced the robust stimulation of JNK1/2 and ERK1/2 MAPKs, FADD, and Akt-mTOR pathways, without apparent increases in apoptotic rates. Interestingly, PDYN deficiency prevented stress-induced JNK1/2 and FADD but not ERK1/2 or Akt-mTOR hyperactivations. These findings suggest that cortico-thalamic MAPK- and FADD-dependent neuroplasticity might be altered in PDYN-KO mice. In addition, the results also indicate that the PDYN gene (and hence dynorphin release) may be required to stimulate JNK1/2 and FADD (but not ERK1/2 or Akt/mTOR) pathways under environmental stress conditions., This joint research was funded by Red Temática de Investigación Cooperativa en Salud–Red de Trastornos Adictivos (RETICS–RTA, Instituto de Salud Carlos III [ISCIII], MCIU/AEI/FEDER), Grupos RD06/0001/0004 (J.M.) and RD06/0001/0003 (J.A.G.-S.). J.M. also received financial support from Proyectos de Investigación en Salud—ISCIII (grant RD. PI18/00576), Red de Investigación en Atención Primaria de Adicciones (grant RD21/0009/0008), and Delegación del Gobierno para el Plan Nacional Sobre Drogas (PNSD, grant 2019I012) from the Spanish Ministry of Health (MSC). This study was also supported by MCIU/AEI/FEDER (grants RTI2018-094414-A-I00 to A.R.-M., PID2019-109323RA-I00 to T.F., and SAF2008-01311 to J.A.G.-S.), and MSC/FEDER (FIS 05/0429 to J.M). A.R.-M. (grant RYC-2016-19282) and T.F. (grant RYC-2017-22666) are ‘Ramón y Cajal’ Researchers.

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).

[Importance] About 20% to 30% of people with schizophrenia have psychotic symptoms that do not respond adequately to first-line antipsychotic treatment. This clinical presentation, chronic and highly disabling, is known as treatment-resistant schizophrenia (TRS). The causes of treatment resistance and their relationships with causes underlying schizophrenia are largely unknown. Adequately powered genetic studies of TRS are scarce because of the difficulty in collecting data from well-characterized TRS cohorts., [Objective] To examine the genetic architecture of TRS through the reassessment of genetic data from schizophrenia studies and its validation in carefully ascertained clinical samples., [Design, Setting, and Participants] Two case-control genome-wide association studies (GWASs) of schizophrenia were performed in which the case samples were defined as individuals with TRS (n = 10 501) and individuals with non-TRS (n = 20 325). The differences in effect sizes for allelic associations were then determined between both studies, the reasoning being such differences reflect treatment resistance instead of schizophrenia. Genotype data were retrieved from the CLOZUK and Psychiatric Genomics Consortium (PGC) schizophrenia studies. The output was validated using polygenic risk score (PRS) profiling of 2 independent schizophrenia cohorts with TRS and non-TRS: a prevalence sample with 817 individuals (Cardiff Cognition in Schizophrenia [CardiffCOGS]) and an incidence sample with 563 individuals (Genetics Workstream of the Schizophrenia Treatment Resistance and Therapeutic Advances [STRATA-G])., [Main Outcomes and Measures] GWAS of treatment resistance in schizophrenia. The results of the GWAS were compared with complex polygenic traits through a genetic correlation approach and were used for PRS analysis on the independent validation cohorts using the same TRS definition., [Results] The study included a total of 85 490 participants (48 635 [56.9%] male) in its GWAS stage and 1380 participants (859 [62.2%] male) in its PRS validation stage. Treatment resistance in schizophrenia emerged as a polygenic trait with detectable heritability (1% to 4%), and several traits related to intelligence and cognition were found to be genetically correlated with it (genetic correlation, 0.41-0.69). PRS analysis in the CardiffCOGS prevalence sample showed a positive association between TRS and a history of taking clozapine (r2 = 2.03%; P = .001), which was replicated in the STRATA-G incidence sample (r2 = 1.09%; P = .04)., [Conclusions and Relevance] In this GWAS, common genetic variants were differentially associated with TRS, and these associations may have been obscured through the amalgamation of large GWAS samples in previous studies of broadly defined schizophrenia. Findings of this study suggest the validity of meta-analytic approaches for studies on patient outcomes, including treatment resistance., This work was supported by Medical Research Council Centre grant MR/L010305/1, Medical Research Council Program grant MR/P005748/1, and Medical Research Council Project grants MR/L011794/1 and MC_PC_17212 to Cardiff University and by the National Centre for Mental Health, funded by the Welsh Government through Health and Care Research Wales. This work acknowledges the support of the Supercomputing Wales project, which is partially funded by the European Regional Development Fund via the Welsh Government. Dr Pardiñas was supported by an Academy of Medical Sciences Springboard Award (SBF005\1083). Dr Andreassen was supported by the Research Council of Norway (grants 283798, 262656, 248980, 273291, 248828, 248778, and 223273); KG Jebsen Stiftelsen, South-East Norway Health Authority, and the European Union’s Horizon 2020 Research and Innovation Programme (grant 847776). Dr Ajnakina was supported by an National Institute for Health Research postdoctoral fellowship (PDF-2018-11-ST2-020). Dr Joyce was supported by the University College London Hospitals/UCL University College London Biomedical Research Centre. Dr Kowalec received funding from the European Union’s Horizon 2020 Research and Innovation Programme under the Marie Skłodowska-Curie grant agreement (793530) from the government of Canada Banting postdoctoral fellowship programme and the University of Manitoba. Dr Sullivan was supported by the Swedish Research Council (Vetenskapsrådet, D0886501), the European Union’s Horizon 2020 programme (COSYN, 610307) and the US National Institute of Mental Health (U01 MH109528 and R01 MH077139). The Psychiatric Genomics Consortium was partly supported by the National Institute Of Mental Health (grants R01MH124873). The Sweden Schizophrenia Study was supported by the National Institute Of Mental Health (grant R01MH077139). The STRATA consortium was supported by a Stratified Medicine Programme grant to Dr MacCabe from the Medical Research Council (grant MR/L011794/1), which funded the research and supported Drs Pardiñas, Smart, Kassoumeri, Murray, Walters, and MacCabe. Dr Smart was supported by a Collaboration for Leadership in Applied Health Research and Care South London at King’s College Hospital National Health Service Foundation Trust. The AESOP (US) cohort was funded by the UK Medical Research Council (grant G0500817). The Belfast (UK) cohort was funded by the Research and Development Office of Northern Ireland. The Bologna (Italy) cohort was funded by the European Community’s Seventh Framework program (HEALTH-F2-2010–241909, project EU-GEI). The Genetics and Psychosis project (London, UK) cohort was funded by the UK National Institute of Health Research Specialist Biomedical Research Centre for Mental Health, South London and the Maudsley National Health Service Mental Health Foundation Trust (SLAM) and the Institute of Psychiatry, Psychology, and Neuroscience at King’s College London; Psychiatry Research Trust; Maudsley Charity Research Fund; and the European Community’s Seventh Framework program (HEALTH-F2-2009-241909, project EU-GEI). The Lausanne (Switzerland) cohort was funded by the Swiss National Science Foundation (grants 320030_135736/1, 320030-120686, 324730-144064, 320030-173211, and 171804); the National Center of Competence in Research Synaptic Bases of Mental Diseases from the Swiss National Science Foundation (grant 51AU40_125759); and Fondation Alamaya. The Oslo (Norway) cohort was funded by the Research Council of Norway (grant 223273/F50, under the Centers of Excellence funding scheme, 300309, 283798) and the South-Eastern Norway Regional Health Authority (grants 2006233, 2006258, 2011085, 2014102, 2015088, and 2017-112). The Paris (France) cohort was funded by European Community’s Seventh Framework program (HEALTH-F2-2010–241909, project EU-GEI). The Prague (Czech Republic) cohort was funded by the Ministry of Health of the Czech Republic (grant NU20-04-00393). The Santander (Spain) cohort was funded by the following grants to Dr Crespo-Facorro: Instituto de Salud Carlos III (grants FIS00/3095, PI020499, PI050427, and PI060507), Plan Nacional de Drogas Research (grant 2005-Orden sco/3246/2004), SENY Fundatio Research (grant 2005-0308007), Fundacion Marques de Valdecilla (grant A/02/07, API07/011) and Ministry of Economy and Competitiveness and the European Fund for Regional Development (grants SAF2016-76046-R and SAF2013-46292-R). The West London (UK) cohort was funded by The Wellcome Trust (grants 042025, 052247, and 064607).

This article belongs to the Special Issue Lipid Mediated Mechanisms in Neurologic and Neuropsychiatric Disease., The therapeutic benefits of the current medications for patients with psychiatric disorders contrast with a great variety of adverse effects. The endocannabinoid system (ECS) components have gained high interest as potential new targets for treating psychiatry diseases because of their neuromodulator role, which is essential to understanding the regulation of many brain functions. This article reviewed the molecular alterations in ECS occurring in different psychiatric conditions. The methods used to identify alterations in the ECS were also described. We used a translational approach. The animal models reproducing some behavioral and/or neurochemical aspects of psychiatric disorders and the molecular alterations in clinical studies in post-mortem brain tissue or peripheral tissues were analyzed. This article reviewed the most relevant ECS changes in prevalent psychiatric diseases such as mood disorders, schizophrenia, autism, attentional deficit, eating disorders (ED), and addiction. The review concludes that clinical research studies are urgently needed for two different purposes: (1) To identify alterations of the ECS components potentially useful as new biomarkers relating to a specific disease or condition, and (2) to design new therapeutic targets based on the specific alterations found to improve the pharmacological treatment in psychiatry., The preparation of the manuscript was supported by “Instituto de Salud Carlos III” (RD. PI18/00576), RD21/0009/0008 “Red de Investigación en Atención Primaria de Adicciones”) and “Delegación del Gobierno para el Plan Nacional Sobre Drogas” (PNSD, 2019I012) from the Spanish Ministry of Health to JM. AB is the recipient of a contract from Grant RD21/0009/0008 of the Spanish Ministry of Health.

Despite substance use disorders (SUD) being one of the leading causes of disability and mortality globally, available therapeutic approaches remain ineffective. The difficulty in accurately characterizing the neurobiological mechanisms involved with a purely qualitative diagnosis is an obstacle to improving the classification and treatment of SUD. In this regard, identifying central and peripheral biomarkers is essential to diagnosing the severity of drug dependence, monitoring therapeutic efficacy, predicting treatment response, and enhancing the development of safer and more effective pharmacological tools. In recent years, the crucial role that the endocannabinoid system (ECS) plays in regulating the reinforcing and motivational properties of drugs of abuse has been described. This has led to studies characterizing ECS alterations after exposure to various substances to identify biomarkers with potential diagnostic, prognostic, or therapeutic utility. This review aims to compile the primary evidence available from rodent and clinical studies on how the ECS components are modified in the context of different substance-related disorders, gathering data from genetic, molecular, functional, and neuroimaging experimental approaches. Finally, this report concludes that additional translational research is needed to further characterize the modifications of the ECS in the context of SUD, and their potential usefulness in the necessary search for biomarkers., The preparation of the manuscript was supported by “Ministerio de Sanidad, Delegación del Gobierno para el Plan Nacional Sobre Drogas” (PNSD, 2019I012 to J.M.), “ISCIII-Redes de Investigación Cooperativa Orientadas a Resultados en Salud (RICORS), Red de Investigación en Atención Primaria de Adicciones (RIAPAd)” (grant number RD21/0009/0008 to J.M.), “Ministerio de Ciencia e Innovación programa Ramón y Cajal” (RYC201722666 to T.F.), and “Turku University hospital” (grant to F.L.-P.).

This article belongs to the Special Issue Molecular Mechanisms Associated with Drug Addiction Vulnerability., Cumulative evidence has pointed out cannabinoid CB2 receptors (CB2r) as a potential therapeutic key target for treating alcohol use disorder (AUD). This review provides the most relevant results obtained from rodent and human studies, including an integrative section focused on the involvement of CB2r in the neurobiology of alcohol addiction. A literature search was conducted using the electronic databases Medline and Scopus for articles. The search strategy was as follows: “Receptor, Cannabinoid, CB2” AND “Alcohol-Related Disorders” AND “human/or patients”; “Receptor, Cannabinoid, CB2” AND “Alcohol” OR “Ethanol” AND “rodents/or mice/or rats”. Pharmacological approaches demonstrated that the activation or blockade of CB2r modulated different alcohol-addictive behaviors. Rodent models of alcoholism revealed significant alterations of CB2r in brain areas of the reward system. In addition, mice lacking CB2r (CB2KO) show increased alcohol consumption, motivation, and relapse alterations. It has been stressed that the potential neurobiological mechanisms underlying their behavioral effects involve critical elements of the alcohol reward system. Interestingly, recent postmortem studies showed CNR2 alterations in brain areas of alcoholic patients. Moreover, although the number of studies is limited, the results revealed an association between some genetic alterations of the CNR2 and an increased risk for developing AUD. This review provides evidence that CB2r may play a role in alcohol addiction. Clinical studies are necessary to figure out whether CB2r ligands may prove useful for the treatment of AUD in humans., The preparation of the manuscript was supported by “Red Primaria de adicciones” (RD21/0009/0008), “Ministerio de Sanidad, Delegación del Gobierno para el Plan Nacional Sobre Drogas” (PNSD, 2019I012 to J.M.), and “Ministerio de Ciencia e Innovación programa Ramón y Cajal” (RYC201722666 to T.F).

This article is part of the Special Issue on ‘Fear, anxiety and PTSD’., Post-traumatic stress disorder (PTSD) is a disabling psychiatric condition with a critical familiar, personal, and social impact. Patients diagnosed with PTSD show various symptoms, including anxiety, depression, psychotic episodes, and sleep disturbances, complicating their therapeutic management. Only sertraline and paroxetine, two selective serotonin reuptake inhibitors, are approved by different international agencies to treat PTSD. In addition, these drugs are generally combined with psychotherapy to achieve positive results. However, these pharmacological strategies present limited efficacy. Nearly half of the PTSD patients do not experience remission of symptoms, possibly due to the high prevalence of psychiatric comorbidities. Therefore, in clinical practice, other off-label medications are common, even though the effectiveness of these drugs needs to be further investigated. In this line, antipsychotics, antiepileptics, adrenergic blockers, benzodiazepines, and other emerging pharmacological agents have aroused interest as potential therapeutic tools to improve some specific symptoms of PTSD. Thus, this review is focused on the most widely used drugs for the pharmacological treatment of PTSD with a translational approach, including clinical and preclinical studies, to emphasize the need to develop safer and more effective medications., This work was supported by “Instituto de Salud Carlos III” (RD.PI18/00576, Spanish Ministerio de Ciencia e Inovación) and ‘Ministerio de Sanidad, Delegación del Gobierno para el Plan Nacional Sobre Drogas’ (PNSD, 2016I016 to J.M.).

Cannabidiol (CBD) may represent a promising therapeutic tool for treating opioid use disorder (OUD). This study was aimed to evaluate the effects of CBD on the behavioural and gene expression alterations induced by spontaneous heroin withdrawal. Thirty hours after cessation of 8-day heroin treatment (5, 10, 20 and 40 mg·kg−1/12 h; s.c.), spontaneous heroin withdrawal was evaluated in CD1 male mice. The effects of CBD (5, 10 and 20 mg·kg−1; i.p.) on withdrawal-related behaviour were evaluated by measuring anxiety-like behaviour, motor activity and somatic signs. Furthermore, gene expression changes of mu-opioid receptor (Oprm1), proopiomelanocortin (Pomc), cannabinoid CB1 (Cnr1) and CB2 (Cnr2) receptors in the nucleus accumbens (NAcc) and tyrosine hydroxylase (TH) and Pomc in the ventral tegmental area (VTA) were also evaluated by real-time PCR. Anxiety-like behaviour, motor activity and withdrawal-related somatic signs were significantly increased in heroin-treated mice compared to the control group. Interestingly, CBD treatment significantly reduced these behavioural impairments and normalized gene expression of Cnr1 and Pomc in the NAcc and TH in the VTA of mice exposed to spontaneous heroin withdrawal. Also, CBD induced an up-regulation of Cnr2, whereas it did not change the increased gene expression of Oprm1 in the NAcc of abstinent animals. The results suggest that CBD alleviates spontaneous heroin withdrawal and normalizes the associated gene expression changes. Future studies are needed to determine the relevance of CBD as a potential therapeutic tool for the treatment of heroin withdrawal., This research was supported by Grants from the ‘Instituto de Salud Carlos III’ (Red de Trastornos Adictivos - RD16/0017/0014, Fondos FEDER) and Ministerio de Sanidad, Consumo y Bienestar Social (Plan Nacional Sobre Drogas - 2019I012) to JM.

This article belongs to the Special Issue Translational Biomarkers in Addictive Disorders., The pharmacological modulation of the cannabinoid receptor 2 (CB2r) has emerged as a promising potential therapeutic option in addiction. The purpose of this review was to determine the functional involvement of CB2r in the effects produced by drugs of abuse at the central nervous system (CNS) level by assessing evidence from preclinical and clinical studies. In rodents, several reports suggest the functional involvement of CB2r in the effects produced by drugs of abuse such as alcohol, cocaine, or nicotine. In addition, the discovery of CB2r in brain areas that are part of the reward system supports the relevance of CB2r in the field of addiction. Interestingly, animal studies support that the CB2r regulates anxiety and depression behavioral traits. Due to its frequent comorbidity with neuropsychiatric disorders, these pharmacological actions may be of great interest in managing SUD. Preliminary clinical trials are focused on exploring the therapeutic potential of modulating CB2r in treating addictive disorders. These promising results support the development of new pharmacological tools regulating the CB2r that may help to increase the therapeutic success in the management of SUD., The preparation of the manuscript was supported by ‘Instituto de Salud Carlos III, Fondos FEDER, Red de Trastornos Adictivos’ (RTA, RD16/0017/0014 to J.M.) and ‘Ministerio de Sanidad, Delegación del Gobierno para el Plan Nacional Sobre Drogas’ (PNSD, 2019I012 to J.M.).

This study evaluated the effects of cannabidiol (CBD) and/or sertraline (STR) on behavioral and gene expression alterations induced by a new chronic animal model of post-traumatic stress disorder (PTSD). C57BL/6J male mice were repeatedly exposed to physical and psychogenic alternate stressful stimuli. Fear-related memory and anxiety-like behaviors were evaluated. The effects of the administration of CBD (20 mg/kg, i.p.) and/or STR (10 mg/kg, p.o.) were analyzed on behavioral and gene expression changes induced by the model of PTSD. Gene expression alterations of targets related with stress regulation, endocannabinoid and serotonergic systems were analyzed by real-time PCR. The results revealed an increased and long-lasting fear-related memory and anxiety-like behaviors in mice exposed to the animal model of PTSD. Treatment with CBD improved these behaviors in PTSD animals, effects that were significantly potentiated when combined with STR. Gene expression analyses revealed a long-term increase of corticotropin releasing factor (Crf) that was significantly normalized with the combination CBD plus STR. Cannabinoid receptors (Cnr1 and Cnr2) were up regulated in PTSD mice whereas the serotonin transporter (Slc6a4) was reduced. Interestingly, CBD and STR alone or combined induced a significant and marked increase of Slc6a4 gene expression. These results point out the cooperative action of the combination CBD plus STR to enhance fear extinction and reduce anxiety-like behaviors, normalizing gene expression alterations in this animal model of PTSD and suggesting that the combination of CBD with STR deserves to be further explored for the treatment of patients with PTSD., This work was supported by “Instituto de Salud Carlos III” (RETICS, RD12/0028/0019 and RD16/0017/0014), “Plan Nacional Sobre Drogas” (PNSD, 2016I016 and 2019I012) and “Ministerio de Economía y Competitividad” (FIS, PI14/00438 and PI18/00576) to JM. We also acknowledge financial support from the Spanish Ministerio de Economía y Competitividad from the “Severo Ochoa” Programme for Centres of Excellence in R&D (SEV-2017-0723).

The coronavirus disease 2019 (COVID-19) outbreak may have affected the mental health of patients at high risk of suicide. In this study we explored the wish to die and other suicide risk factors using smartphone-based ecological momentary assessment (EMA) in patients with a history of suicidal thoughts and behaviour. Contrary to our expectations we found a decrease in the wish to die during lockdown. This is consistent with previous studies showing that suicide rates decrease during periods of social emergency. Smartphone-based EMA can allow us to remotely assess patients and overcome the physical barriers imposed by lockdown. This study received grant support from Instituto de Salud Carlos III (ISCIII PI13/02200; PI16/ 01852; CM19/00026), Delegación del Gobierno para el Plan Nacional de Drogas (20151073), the American Foundation for Suicide Prevention (LSRG-1-005-16), the Ministerio de Ciencia, Innovación y Universidades (RTI2018-099655-B-I00; TEC2017-92552-EXP) and by the Comunidad de Madrid (Y2018/TCS-4705, PRACTICO-CM).

Purpose The nucleus accumbens (NAcc) has been suggested as a possible target for deep brain stimulation (DBS) in the treatment of obesity. Our hypothesis was that NAcc-DBS would modulate brain regions related to reward and food intake regulation, consequently reducing the food intake and, finally, the weight gain. Therefore, we examined changes in brain glucose metabolism, weight gain and food intake after NAcc-DBS in a rat model of obesity. Procedures Electrodes were bilaterally implanted in 2 groups of obese Zucker rats targeting the NAcc. One group received stimulation one hour daily during 15 days, while the other remained as control. Weight and daily consumption of food and water were everyday registered the days of stimulation, and twice per week during the following month. Positron emission tomography (PET) studies with 2-deoxy-2-[F-18] fluoro-D-glucose (FDG) were performed 1 day after the end of DBS. PET data was assessed by statistical parametric mapping (SPM12) software and region of interest (ROI) analyses. Results NAcc-DBS lead to increased metabolism in the cingulate-retrosplenial-parietal association cortices, and decreased metabolism in the NAcc, thalamic and pretectal nuclei. Furthermore, ROIs analyses confirmed these results by showing a significant striatal and thalamic hypometabolism, and a cortical hypermetabolic region. However, NAcc-DBS did not induce a decrease in either weight gain or food intake. Conclusions NAcc-DBS led to changes in the metabolism of regions associated with cognitive and reward systems, whose impairment has been described in obesity. This research was supported by the Ministry of Economy and Competitiveness ISCIII grants (PI14/00860, CPII14/00005), Ministry of Economy, Industry and Competitiveness (PI17/01766), cofunded by ERDF (FEDER) Funds from the European Commission ``A way of making Europe´´, Fundacion Mapfre, Fundacion Alicia Koplowitz (FAK2016/01), `Delegacion de Gobierno para el Plan Nacional sobre Drogas' (PNSD 2017/085), Comunidad de Madrid (BRADE-CM S2013/ICE-2958) and Fundacion Tatiana Perez de Guzman el Bueno. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript. Sí

[Background and Purpose] The aim of this study was to explore if the administration of naltrexone together with cannabidiol (CBD) may improve the efficacy in reducing alcohol consumption and motivation rather than any of the drugs given separately., [Experimental Approach] The effects of low doses of naltrexone (0.7 mg·kg−1, p.o.) and/or CBD (20 mg·kg−1·day−1, s.c.) on ethanol consumption and motivation to drink were evaluated in the oral-ethanol self-administration paradigm in C57BL/6 mice. Gene expression analyses of the opioid μ receptor (Oprm1) in the nucleus accumbens (NAc), tyrosine hydroxylase (TH) in the ventral tegmental area (VTA) and the 5-HT1A receptor in the dorsal raphe nucleus (DR) were carried out by real-time PCR. The role of 5-HT1A receptors in the ethanol reduction induced by the administration of CBD + naltrexone was analysed by using the 5-HT1A receptor antagonist WAY100635 (0.3 mg·kg−1, i.p.)., [Key Results] The administration of CBD + naltrexone significantly reduced motivation and ethanol intake in the oral self-administration procedure in a greater proportion than the drugs given alone. Only the combination of both drugs significantly reduced Oprm1, TH and 5-HT1A gene expressions in the NAc, VTA and DR respectively. Interestingly, the administration of WAY100635 significantly blocked the actions of CBD + naltrexone but had no effects by itself., [Conclusion and Implications]The combination of low doses of CBD plus naltrexone were more effective than either CBD or naltrexone alone at reducing ethanol consumption and the motivation to drink. These effects appear to be mediated, at least in part, by 5-HT1A receptors., This research was supported by ‘Instituto de Salud Carlos III’ (RETICS, RD12/0028/0019 and RD16/0017/0014), ‘Plan Nacional Sobre Drogas’ (PNSD 2016/016) and ‘Ministerio de Economía y Competitividad’ (FIS, PI14/00438) to J.M.; A.V.-M. is a predoctoral fellow supported by ‘Plan Nacional Sobre Drogas’ (PNSD 2016/016).

This study evaluated the effects of cannabidiol (CBD) on ethanol reinforcement, motivation and relapse in C57BL/6 J mice. The effects of CBD (60 mg/kg, i.p.) on blood ethanol concentration, hypothermia and handling-induced convulsions associated to acute ethanol administration were evaluated. The two-bottle choice paradigm was performed to assess the effects of CBD (30, 60 and 120 mg/kg/day, i.p.) on ethanol intake and preference. In addition, an oral ethanol self-administration experiment was carried out to evaluate the effects of CBD [a single s.c. administration of a microparticle formulation providing CBD continuous controlled release (30 mg/kg/day)] on the reinforcement and motivation for ethanol. The effects of CBD (60 and 120 mg/kg/day, i.p.) on ethanol-induced relapse were also evaluated. Gene expression analyses of tyrosine hydroxylase in ventral tegmental area and μ-opioid (Oprm1), cannabinoid (CB1 r and CB2 r) and GPR55 receptors in nucleus accumbens (NAcc) were carried out by real-time polymerase chain reaction. Cannabidiol reduced the ethanol-induced hypothermia and handling-induced convulsion but failed to modify blood ethanol concentration. CBD reduced ethanol consumption and preference in the two-bottle choice, significantly decreased ethanol intake and the number of effective responses in the oral ethanol self-administration, and reduced ethanol-induced relapse. Furthermore, the administration of CBD significantly reduced relative gene expression of tyrosine hydroxylase in the ventral tegmental area, Oprm1, CB1 r and GPR55 in the NAcc and significantly increased CB2 r in the NAcc. Taken together, these results reveal that the administration of CBD reduced the reinforcing properties, motivation and relapse for ethanol. These findings strongly suggest that CBD may result useful for the treatment of alcohol use disorders., This research was supported by ‘Instituto de Salud Carlos III’ (RETICS, RD12/0028/0019), ‘Plan Nacional Sobre Drogas’ (PNSD 2016/016) and ‘Ministerio de Economía y Competitividad’ (FIS, PI14/00438). Adrián Viudez-Martínez is a predoctoral fellow supported by ‘Plan Nacional Sobre Drogas’ (PNSD 2016/016).

[Background and purpose]: Cannabidiol (CBD) represents a promising therapeutic tool for treating cannabis use disorder (CUD). This study aimed to evaluate the effects of CBD on the behavioural and gene expression alterations induced by spontaneous cannabinoid withdrawal., [Experimental approach]: Spontaneous cannabinoid withdrawal was evaluated 12 h after cessation of CP-55,940 treatment (0.5 mg·kg-1 every 12 h, i.p.; 7 days) in C57BL/6J mice. The effects of CBD (5, 10 and 20 mg·kg-1 , i.p.) on withdrawal-related behavioural signs were evaluated by measuring motor activity, somatic signs and anxiety-like behaviour. Furthermore, gene expression changes in TH in the ventral tegmental area, and in the opioid μ receptor (Oprm1), cannabinoid CB1 receptor (Cnr1) and CB2 receptor (Cnr2) in the nucleus accumbens, were also evaluated using the real-time PCR technique., [Key results]: The administration of CBD significantly blocked the increase in motor activity and the increased number of rearings, rubbings and jumpings associated with cannabinoid withdrawal, and it normalized the decrease in the number of groomings. However, CBD did not change somatic signs in vehicle-treated animals. In addition, the anxiogenic-like effect observed in abstinent mice disappeared with CBD administration, whereas CBD induced an anxiolytic-like effect in non-abstinent animals. Moreover, CBD normalized gene expression changes induced by CP-55,940-mediated spontaneous withdrawal., [Conclusions and implications]: The results suggest that CBD alleviates spontaneous cannabinoid withdrawal and normalizes associated gene expression changes. Future studies are needed to determine the relevance of CBD as a potential therapeutic tool for treating CUD., This research was supported by the ‘Instituto de Salud Carlos III’ (RTA, RD12/0028/0019 and RD16/0017/0014, Fondos FEDER), ‘Plan Nacional Sobre Drogas’ (PNSD 2016/016) and ‘Ministerio de Economía y Competitividad’ (FIS, PI14/00438).

Anxiety and alcohol use disorders (AUD) often present together, constituting a significant public health problem worldwide. In this study, we investigated the role of DLK1, a ligand of the Delta/NOTCH epidermal growth factor (EGF)-like protein family, reported to play a role in DA neurons differentiation in the striatum, as a neurobiological factor involved in the mechanisms regulating this psychiatric comorbidity. We exposed Dlk1 knockout mice (Dlk1−/− mice) to the open-field (OF), the light-dark box (LBD) and the elevated plus maze (EPM) tests, evaluating motivation to drink and ethanol consumption using the oral ethanol self-administration (OEA) paradigm. Quantitative real time polymerase chain reaction (qPCR) studies were carried out to evaluate alterations in targets closely related to DA neurotransmission in the reward system, tyrosine hydroxylase (Th) in the ventral tegmental area (VTA), and μ-opioid receptor (Oprm1) in the nucleus accumbens (NAc). No differences were observed in the total or peripheral distances travelled by Dlk1−/− compared to wild-type (WT) mice in OF. However, central distance travelled significantly decreased in Dlk1−/− mice. Deletion of Dlk1 increased anxiety-like behaviors in the LDB and EPM, and, Dlk1−/− mice also presented higher ethanol intake and motivation to drink (number of effective responses) in the OEA. In addition, Th and Oprm1 gene expression was reduced in the VTA and NAc of Dlk1−/− mice. We conclude that deletion of Dlk1 increases anxiety-related behaviors and vulnerability to ethanol consumption and modifies the gene expression of key targets closely related with DA neurotransmission involved in the reinforcing actions of ethanol., This research was supported by Health Institute Carlos III (Retics, RD16/0017/0014), National Plan on Drug Abuse (PNSD 2016/016) and the Spanish Ministry of Economics and Competitivity (FIS, PI14/00438) to JM, and by Department of Education, Culture and Sports (European Regional Development Fund, Council of Communities of Castilla la Mancha, Spain (PEII-2014-033-P) to JL.

Inflammatory cytokines and reactive oxygen species are reported to be involved in blood–brain barrier (BBB) disruption. Because there is evidence that ethanol (EtOH) induces release of free radicals, cytokines and inflammatory mediators we examined BBB integrity and matrix metalloproteinase (MMP) activity in postmortem human alcoholic brain and investigated the role of TLR4 signaling in BBB permeability in TLR4-knockout mice under a binge-like EtOH drinking protocol. Immunohistochemical studies showed reduced immunoreactivity of the basal lamina protein, collagen-IV and of the tight junction protein, claudin-5 in dorsolateral prefrontal cortex of alcoholics. There was also increased MMP-9 activity and expression of phosphorylated ERK1/2 and p-38. Greater number of CD45+ IR cells were observed associated with an enhanced neuroinflammatory response reflected by increased GFAP and Iba-1 immunostaining. To further explore effects of high EtOH consumption on BBB integrity we studied TLR4-knockout mice exposed to the drinking in the dark paradigm. Repetitive EtOH exposure in wild-type mice decreased hippocampal expression of laminin and collagen-IV and increased IgG immunoreactivity, indicating IgG extravasation. Western blot analysis also revealed increased MyD88 and p-ERK1/2 levels. None of these changes was observed in TLR4-knockout mice. Collectively, these findings indicate that chronic EtOH increases degradation of tight junctions and extracellular matrix in postmortem human brain and induces a neuroinflammatory response associated with activation of ERK1/2 and p-38 and greater MMP-9 activity. The EtOH-induced effects on BBB impairment are not evident in the hippocampus of TLR4-knockout mice, suggesting the involvement of TLR4 signaling in the underlying mechanism leading to BBB disruption in mice., This work was supported by grants from the Spanish Ministerio de Economia y Competitividad (MINECO) (SAF2010-21529 and SAF2013-40592-R to MIC and SAF 2011-23420 to JM), Ministerio de Sanidad, Servicios Sociales e Igualdad (PNSD 2011/043 to JM, PNSD 2013I077 to EOS and PNSD 2014I015 to MIC), ISCIII RETICS RTA (RD06/0001/0006 and RD12/0028/0002 to MIC and RD06/0001/1004 and RD12/0028/0019 to JM), Universidad Complutense (UCM 910258 to MIC) and Consejeria de Educacion y Empleo, Comunidad de Madrid. (CAM S2010-BMD-2308 to MIC). ARA is the recipient of a RETICS RTA post-doctoral contract; MPH and FP are recipients of pre-doctoral fellowships from the Ministerio de Educacion (Spain) and Regione Autonoma Della Sardegna (Italy), respectively.