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Progesterone (PRG) and testosterone (TST) were impregnated on mesoporous silica (ExP) particles via supercritical carbon dioxide (scCO2) processing at various pressures (10–18 MPa), temperatures (308.2–328.2 K), and time (30–360 min). The impact of a co-solvent on the impregnation was also studied at the best determined pressure and temperature. The properties of the drug embedded in silica particles were analysed via gas chromatography (GC), attenuated total reflectance-Fourier transform infrared (ATR-FTIR) spectroscopy, X-ray diffraction (XRD), differential scanning calorimetry (DSC), and nitrogen adsorption. An impregnation of 1 to 82 mg/g for PRG and 0.1 to 16 mg/g for TST was obtained depending on the processing parameters. There was a significant effect of pressure, time, and co-solvent on the impregnation efficiency. Generally, an increase in time and pressure plus the use of co-solvent led to an improvement in drug adsorption. Conversely, a rise in temperature resulted in lower impregnation of both TST and PRG on ExP. There was a substantial increase in the dissolution rate (> 90% drug release within the first 2 min) of both TST and PRG impregnated in silica particles when compared to the unprocessed drugs. This dissolution enhancement was attributed to the amorphisation of both drugs due to their adsorption on mesoporous silica. Graphical Abstract

Panic-like reactions elicited by electrical stimulation of the dorsal periaqueductal grey matter (ES-dPAG) seem to be regulated by dopamine (DA). We showed that DA applied intranasally (IN) increased escape-behaviour thresholds induced by ES-dPAG of rats, indicating a panicolytic-like effect.We investigated whether IN-DA increases escape-response thresholds induced by ES-dPAG by acting on DWistar rats exposed to ES-dPAG were treated with Sulpiride (SUL, 40 mg/kg, DAnti-aversive effects of the IN-DA were reduced by SUL pretreatment in the ES-dPAG test. IN-DA did not affect the escape number in the PSP nor the escape latencies in the ETM as well as motor performance in the OF.The IN-DA effects in reducing unconditioned fear responses elicited by ES-dPAG seem to be mediated by D

Hedgehog morphogens control fundamental cellular processes during tissue development and regeneration. In the central nervous system (CNS), Hedgehog signaling has been implicated in oligodendrocyte and myelin production, where it functions in a concerted manner with other pathways. Since androgen receptor (AR) plays a key role in establishing the sexual phenotype of myelin during development and is required for spontaneous myelin regeneration in the adult CNS, we hypothesized the existence of a possible coordination between Hedgehog and androgen signals in oligodendrocyte and myelin production. Here, we report complementary activities of both pathways during early postnatal oligodendrogenesis further revealing that persistent Hedgehog signaling activation impedes myelin production. The data also uncover prominent pro-myelinating activity of testosterone and involvement of AR in the control of neural stem cell commitment toward the oligodendroglial lineage. In the context of CNS demyelination, we provide evidence for the functional cooperation of the pathways leading to acceleration of myelin regeneration that might be related to their respective role on microglial and astroglial responses, higher preservation of axonal integrity, lower neuroinflammation, and functional improvement of animals in an immune model of CNS demyelination. Strong decreases of deleterious cytokines in the CNS (GM-CSF, TNF-α, IL-17A) and spleen (IL-2, IFN-γ) stand as unique features of the combined drugs while the potent therapeutic activity of testosterone on peripheral immune cells contributes to increase tolerogenic CD11c+ dendritic cells, reduce the clonal expansion of conventional CD4+ T cells and increase CD4+ Foxp3+ regulatory T cells. Altogether, these data might open promising perspectives for demyelinating diseases.

Background: Panic-like reactions elicited by electrical stimulation of the dorsal periaqueductal grey matter (ES-dPAG) seem to be regulated by dopamine (DA). We showed that DA applied intranasally (IN) increased escape-behaviour thresholds induced by ES-dPAG of rats, indicating a panicolytic-like effect. Aims: We investigated whether IN-DA increases escape-response thresholds induced by ES-dPAG by acting on D2-like receptors, and whether IN-DA affects escape responses elicited by the presence of a potential predator and by open space and height of the elevated T-maze (ETM) as well as motor performance in the open field (OF) test. Methods: Wistar rats exposed to ES-dPAG were treated with Sulpiride (SUL, 40 mg/kg, D2-like receptor antagonist) previously IN-DA (2 mg/kg). Independent groups of rats treated with IN-DA were submitted to prey versus snake paradigm (PSP), ETM and OF. Results: Anti-aversive effects of the IN-DA were reduced by SUL pretreatment in the ES-dPAG test. IN-DA did not affect the escape number in the PSP nor the escape latencies in the ETM as well as motor performance in the OF. Conclusions/interpretation: The IN-DA effects in reducing unconditioned fear responses elicited by ES-dPAG seem to be mediated by D2-like receptors. The lack of effects on panic-related responses in the ETM and PSP may be related to the possibility of avoiding the danger inherent to these models, a defence strategy not available during ES-dPAG. These findings cannot be attributed to motor performance. The decision-making responses to avoid dangerous situations can be orchestrated by supra-mesencephalic structures connected by non-dopaminergic inputs.

Studies on the attention-deficit/hyperactivity disorder (ADHD) have concluded that the disorder might be caused by a deficit in the inhibitory control of executive functions because of dopamine hypofunction. Recently, the intranasal route has emerged as an effective alternative means for sending dopamine directly to the brain. However, whether the treatment can ameliorate the deficits of inhibitory control in ADHD remains unknown. Investigating the effects of acute intranasal dopamine (IN-DA) on the inhibitory control of executive functions of an ADHD rodent model. We trained an animal model of ADHD, the spontaneously hypertensive rat (SHR), and Wistar rats as controls, in an attentional set-shifting task (ASST) in which dopamine (0.15 mg/kg, 0.3 mg/kg, or vehicle) was intranasally administered before the final test. IN-DA application dose-dependently improved the performance and reduced errors of SHR in the initial reversal learning. The effect size was comparable to that of a peripheral injection of 0.6 mg/kg methylphenidate. In control Wistar rats, the highest dose of intranasal dopamine (0.3 mg/kg) induced deficits in the reversal learning of extradimensional discriminations. The findings suggest that the IN-DA treatment has potential for use in the treatment of ADHD; however, caution must be exercised when determining the dosage to be administered, because too much dopamine may have negative effects.

The dopamine (DA) system has a profound impact on reward-motivated behavior and is critically involved in neurodevelopmental disorders, such as autism spectrum disorder (ASD). Although DA defects are found in autistic patients, it is not well defined how the DA pathways are altered in ASD and whether DA can be utilized as a potential therapeutic agent for ASD. To this end, we employed a phenotypic and a genetic ASD model, i.e., Black and Tan BRachyury T+Itpr3tf/J (BTBR) mice and Fragile X Mental Retardation 1 knockout (Fmr1-KO) mice, respectively. Immunostaining of tyrosine hydroxylase (TH) to mark dopaminergic neurons revealed an overall reduction in the TH expression in the substantia nigra, ventral tegmental area and dorsal striatum of BTBR mice, as compared to C57BL/6J wild-type ones. In contrast, Fmr1-KO animals did not show such an alteration but displayed abnormal morphology of TH-positive axons in the striatum with higher “complexity” and lower “texture”. Both strains exhibited decreased expression of striatal dopamine transporter (DAT) and increased spatial coupling between vesicular glutamate transporter 1 (VGLUT1, a label for glutamatergic terminals) and TH signals, while GABAergic neurons quantified by glutamic acid decarboxylase 67 (GAD67) remained intact. Intranasal administration of DA rescued the deficits in non-selective attention, object-based attention and social approaching of BTBR mice, likely by enhancing the level of TH in the striatum. Application of intranasal DA to Fmr1-KO animals alleviated their impairment of social novelty, in association with reduced striatal TH protein. These results suggest that although the DA system is modified differently in the two ASD models, intranasal treatment with DA effectively rectifies their behavioral phenotypes, which may present a promising therapy for diverse types of ASD.

The Disrupted-in-Schizophrenia 1 (DISC1) gene has been associated with mental illnesses such as major depression and schizophrenia. The transgenic DISC1 (tgDISC1) rat, which overexpresses the human DISC1 gene, is known to exhibit deficient dopamine (DA) homeostasis. To ascertain whether the DISC1 gene also impacts cognitive functions, 14–15 months old male tgDISC1 rats and wild-type controls were subjected to the novel object preference (NOP) test and the object-based attention test (OBAT) in order to assess short-term memory (1 h), long-term memory (24 h), and attention. Results: The tgDISC1 group exhibited intact short-term memory, but deficient long-term-memory in the NOP test and deficient attention-related behavior in the OBAT. In a different group of tgDISC1 rats, 3 mg/kg intranasally applied dopamine (IN-DA) or its vehicle was applied prior to the NOP or the OBAT test. IN-DA reversed cognitive deficits in both the NOP and OBAT tests. In a further cohort of tgDISC1 rats, post-mortem levels of DA, noradrenaline, serotonin and acetylcholine were determined in a variety of brain regions. The tgDISC1 group had less DA in the neostriatum, hippocampus and amygdala, less acetylcholine in neostriatum, nucleus accumbens, hippocampus, and amygdala, more serotonin in the nucleus accumbens, and less serotonin and noradrenaline in the amygdala. Conclusions: Our findings show that DISC1 overexpression and misassembly is associated with deficits in long-term memory and attention-related behavior. Since behavioral impairments in tgDISC1 rats were reversed by IN-DA, DA deficiency may be a major cause for the behavioral deficits expressed in this model.

Our previous studies showed that intranasal delivery of progesterone offers a good bioavailability and neuroprotective efficacy after experimental stroke. We have also demonstrated that progesterone receptors (PR) are essential for cerebroprotection by endogenous progesterone and by progesterone treatment. The identification of PR as a potential drug target for stroke therapy opens new therapeutic indications for selective synthetic progestins. Nestorone® (16-methylene-17α-acetoxy-19-nor-pregn-4-ene-3, 20-dione, also known as segesterone acetate) is a 19-norprogesterone derivative that more potently targets PR than progesterone. The objective of this study was to evaluate the cerebroprotective efficiency of intranasal administration of Nestorone after middle cerebral occlusion (MCAO) in mice. We show here that intranasal administration is a very efficient route to achieve a preferential delivery of Nestorone to the brain and confers a slow elimination and a sustained bioavailability. Furthermore, intranasal administration of Nestorone (at 0.08 mg/kg) improved the functional outcomes and decreased the ischemic lesion in male but not in female mice at 48 h post MCAO. Use of PRNesCre mice, selectively lacking expression of PR in neural cells, and their control PRloxP/loxP littermates showed that the cerebroprotective effects of Nestorone in male mice depended on neural PR as they were not observed in PRNesCre mice. Our findings show that intranasal delivery of Nestorone may be an efficient strategy to promote recovery after stroke in males and confirm the key role of PR in cerebroprotection. Furthermore, they point to sex differences in the response to Nestorone treatment and emphasize the necessity to include males and females in experimental studies.

Treatment with progesterone protects the male and female brain against damage after middle cerebral artery occlusion (MCAO). However, in both sexes, the brain contains significant amounts of endogenous progesterone. It is not known whether endogenously produced progesterone enhances the resistance of the brain to ischemic insult. Here, we used steroid profiling by gas chromatography-tandem mass spectrometry (GC-MS/MS) for exploring adaptive and sex-specific changes in brain levels of progesterone and its metabolites after MCAO. We show that, in the male mouse brain, progesterone is mainly metabolized via 5α-reduction leading to 5α-dihydroprogesterone (5α-DHP), also a progesterone receptor (PR) agonist ligand in neural cells, then to 3α,5α-tetrahydroprogesterone (3α,5α-THP). In the female mouse brain, levels of 5α-DHP and 3α,5α-THP are lower and levels of 20α-DHP are higher than in males. After MCAO, levels of progesterone and 5α-DHP are upregulated rapidly to pregnancy-like levels in the male but not in the female brain. To assess whether endogenous progesterone and 5α-DHP contribute to the resistance of neural cells to ischemic damage, we inactivated PR selectively in the CNS. Deletion of PR in the brain reduced its resistance to MCAO, resulting in increased infarct volumes and neurological deficits in both sexes. Importantly, endogenous PR ligands continue to protect the brain of aging mice. These results uncover the unexpected importance of endogenous progesterone and its metabolites in cerebroprotection. They also reveal that the female reproductive hormone progesterone is an endogenous cerebroprotective neurosteroid in both sexes.SIGNIFICANCE STATEMENTThe brain responds to injury with protective signaling and has a remarkable capacity to protect itself. We show here that, in response to ischemic stroke, levels of progesterone and its neuroactive metabolite 5α-dihydroprogesterone are upregulated rapidly in the male mouse brain but not in the female brain. An important role of endogenous progesterone in cerebroprotection was demonstrated by the conditional inactivation of its receptor in neural cells. These results show the importance of endogenous progesterone, its metabolites, and neural progesterone receptors in acute cerebroprotection after stroke. This new concept could be exploited therapeutically by taking into account the progesterone status of patients and by supplementing and reinforcing endogenous progesterone signaling for attaining its full cerebroprotective potential.

Background: Although substantial evidence suggests that dopamine (DA) enhances conditioned fear responses, few studies have examined the role of DA in unconditioned fear states. Whereas DA does not cross the blood–brain barrier, intranasally-applied dopamine reaches the brain directly via the nose–brain pathways in rodents, providing an alternative means of targeting DA receptors. Intranasal dopamine (IN-DA) has been demonstrated to bind to DA transporters and to increase extracellular DA in the striatum as well as having memory-promoting effects in rats. The purpose of this study was to examine the influence of IN-DA in three tests of fear/anxiety. Methods: The three doses of DA hydrochloride (0.03, 0.3, or 1 mg/kg) were applied in a viscous castor oil gel in a volume of 5 µl to each of both nostrils of adult Wistar rats prior to testing of (a) escape from a bright light, using a two-chamber procedure, (b) restraint-induced 22 kHz ultrasound vocalizations (USVs), and (c) exploratory behavior in the elevated plus-maze (EPM). Results: IN-DA dose-dependently reduced escape from bright light and the number of USV responses to restraint. It had no influence on the exploratory behavior in the EPM. Conclusions: IN-DA application reduced escape behavior in two tests of unconditioned fear (escape from bright light and USV response to immobilization). These findings may be interpreted in light of the known antidepressant action of IN-DA and DA reuptake blockers. The results also confirm the promise of the nasal route as an alternative means for targeting the brain’s dopaminergic receptors with DA.

Intranasal administration is emerging as a very promising route to deliver therapeutics to the brain. We have recently shown that the intranasal delivery of progesterone at 8 mg/kg is neuroprotective after stroke in male mice. To explore the translational potential of intranasal progesterone treatment, we performed a dose-response study and analyzed outcomes at 48 h after middle cerebral artery occlusion (MCAO). The effects on functional outcomes at long-term were examined by using the optimal dose. In the first experiment, male C57BL/6JRj mice were treated with progesterone at 8, 16 or 24 mg/kg, or with placebo at 1, 6 and 24 h post-MCAO. Our results show that the dose of 8 mg/kg was optimal in counteracting the early histopathological impairments as well as in improving functional recovery. Steroid profiling in plasma showed that the dose of 8 mg/kg is the one that leads to sustained high levels of progesterone and its neuroactive metabolites. In the second experiment, the dose of 8 mg/kg was used and analyzes were performed at 2, 7 and 21 days post-MCAO. Progesterone increased survival, glycemia and body weight. Furthermore, progesterone decreased neurological deficits and improved performances of mice on the rotarod and pole as early as 2 days and up to 21 days post-MCAO. These findings show that intranasal administration of progesterone has a significant translational potential as a cerebroprotective treatment after stroke that can be effective to reduce mortality, to limit tissue and cell damage at the acute phase; and to confer a long-term functional recovery.

Purpose:Intranasally applied dopamine (IN-DA), which likely reaches the brain via nasal–brain pathways and bypasses the blood–brain barrier, has been found to increase extracellular DA and bind to the DA2 transporter in the striatum. Recent studies suggest that DA plays a significant role in the processing of signaled and unconditioned aversive stimulation, including evidence that may attenuate responses to painful input. The purpose of this study was to examine the effects of IN-DA on fear-related behaviors induced by electric shock to the foot or by electrical stimulation of the dorsal periaqueductal gray matter (dPAG).Methods:DA hydrochloride suspended in a viscous castor oil gel (1 or 2 mg/kg) was applied (IN-DA) in a volume of 5 μL into the nostrils of adult Wistar male rats in order to evaluate its effects on (a) freezing induced by electric shock to the foot and (b) thresholds of freezing and escape and duration of post-stimulation freezing induced by electrical stimulation of the dPAG.Results:IN-DA attenuated freezing induced by electric shock to the foot in the three test trials, indicating that it reduced long-term fear responses. IN-DA also increased the threshold of dPAG stimulation-induced escape responses and reduced post-stimulation freezing.Conclusions:IN-DA, which has previously been shown to facilitate learning and to have antidepressive-like effects, attenuated unconditioned fear responses elicited by peripheral and intramesencephalic (dPAG) stimulation and reduced long-term conditioned fear responses.

This study determined the effects of intranasal pregnenolone (IN-PREG) on acetylcholine (ACh) levels in selected areas of the rat brain, using in vivo microdialysis. Previous studies showed that PREG rapidly reaches the rodent brain after intranasal administration and that direct infusion of PREG and PREG-S into the basal forebrain modulates ACh release in frontal cortex, amygdala, and hippocampus. In the present study, we investigated the effects of IN-PREG on the cholinergic system in the rat brain. In the first experiment, IN-PREG (5.6 and 11.2 mg/ml) or vehicle was applied bilaterally, and we hypothesized that IN-PREG would increase ACh levels in amygdala, hippocampus, and frontal cortex, relative to baseline and vehicle. Dialysate was collected for 100 min, based on pilot data of duration of effect. Bilateral IN-PREG (5.6 and 11.2 mg/ml) increased frontal cortex and hippocampal ACh relative to both baseline and vehicle. Moreover, 11.2 mg/ml PREG increased ACh in the amygdala relative to baseline, the lower dose, and vehicle. Therefore, in the second experiment, IN-PREG (11.2 mg/ml) was applied only into one nostril, with vehicle applied into the other nostril, in order to determine whether ACh is predominantly increased in the ipsilateral relative to the contralateral amygdala. Unilateral application of IN-PREG increased ACh in the ipsilateral amygdala, whereas no effect was observed on the contralateral side, suggesting that PREG was transported from the nostrils to the brain via the olfactory epithelial pathway, but not by circulation. The present data provide additional information on IN-PREG action in the cholinergic system of frontal cortex, amygdala, and hippocampus. This may be relevant for therapeutic IN application of PREG in neurogenerative and neuropsychiatric disorders.

Levels of steroids in the adult central nervous system (CNS) show marked changes in response to stress, degenerative disorders and injury. However, their analysis in complex matrices such as fatty brain and spinal cord tissues, and even in plasma, requires accurate and precise analytical methods. Radioimmunoassays (RIA) and enzyme-linked immunosorbent assays, even with prepurification steps, do not provide sufficient specificity, and they are at the origin of many inconsistent results in the literature. The analysis of steroids by mass spectrometric methods has become the gold standard for accurate and sensitive steroid analysis. However, these technologies involve multiple purification steps prone to errors, and they only provide accurate reference values when combined with careful sample workup. In addition, the interpretation of changes in CNS steroid levels is not an easy task because of their multiple sources: the endocrine glands and the local synthesis by neural cells. In the CNS, decreased steroid levels may reflect alterations of their biosynthesis, as observed in the case of chronic stress, post-traumatic stress disorders or depressive episodes. In such cases, return to normalization by administering exogenous hormones or by stimulating their endogenous production may have beneficial effects. On the other hand, increases in CNS steroids in response to acute stress, degenerative processes or injury may be part of endogenous protective or rescue programs, contributing to the resistance of neural cells to stress and insults. The aim of this review is to encourage a more critical reading of the literature reporting steroid measures, and to draw attention to the absolute need for well-validated methods. We discuss reported findings concerning changing steroid levels in the nervous system by insisting on methodological issues. An important message is that even recent mass spectrometric methods have their limits, and they only become reliable tools if combined with careful sample preparation. Fil: Schumacher, Michael. Inserm; Francia. Universite Paris Sud; Francia Fil: Guennoun, Rachida. Inserm; Francia. Universite Paris Sud; Francia Fil: Mattern, Claudia. M et P Pharma AG; Suiza Fil: Oudinet, Jean Paul. Inserm; Francia. Universite Paris Sud; Francia Fil: Labombarda, Maria Florencia. Universidad de Buenos Aires. Facultad de Medicina; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Biología y Medicina Experimental (i); Argentina Fil: de Nicola, Alejandro Federico. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Biología y Medicina Experimental (i); Argentina. Universidad de Buenos Aires. Facultad de Medicina; Argentina Fil: Liere, Phillippe. Inserm; Francia

Progesterone has been shown to be cerebroprotective in different experimental models of brain injuries and neurodegenerative diseases. The preclinical data provided great hope for its use in humans. The failure of Phase 3 clinical trials to demonstrate the cerebroprotective efficiency of progesterone in traumatic brain injury (TBI) patients emphasizes that different aspects of the design of both experimental and clinical studies should be reviewed and refined. One important aspect to consider is to test different routes of delivery of therapeutic agents. Several studies have shown that the intranasal delivery of drugs could be used in different experimental models of central nervous system diseases. In this review, we will summarize the pharmacokinetic characteristics and practical advantages of intranasal delivery of progesterone. A special emphasis will be placed on describing and discussing our recent findings showing that intranasal delivery of progesterone after transient focal cerebral ischemia: 1) improved motor functions; 2) reduced infarct volume, neuronal loss, blood brain barrier disruption; and 3) reduced brain mitochondrial dysfunctions. Our data suggest that intranasal delivery of progesterone is a potential efficient, safe and non-stressful mode of administration that warrants evaluation for cerebroprotection in patients with brain injuries. This article is part of the Special Issue entitled "Novel Treatments for Traumatic Brain Injury".

Progesterone is a potential neuroprotective agent for cerebral stroke. One of the STAIR's recommendations is to test different routes of delivery of therapeutic agents. Here, we investigated the neuroprotective efficacy of intranasal delivery of progesterone in oleogel. Male mice were subjected to transient middle cerebral occlusion (MCAO) for 1 h. Mice received intranasal or intraperitoneal administrations of progesterone (8 mg/kg) at 1, 6, and 24 h post-MCAO. Plasma and brain levels of steroids were measured by gas chromatography-mass spectrometry 2 and 24 h after the last administration of progesterone. Behavioral and histopathological analyzes were performed at 48 h post-MCAO. For blood-brain barrier (BBB) permeability analysis, mice received one intranasal administration of progesterone or placebo at reperfusion and Evans Blue and sodium fluorescein extravasations were assessed at 4 h post-MCAO. Two hours after its nasal administration, progesterone reached elevated levels in brain and plasma and was bioconverted to its 5α-reduced metabolites and to 20α-dihydroprogesterone. However, brain levels of progesterone and its metabolites were about half those measured after intraperitoneal injections, whereas levels of 11-deoxycorticosterone and corticosterone were 5-times lower. In contrast, after 24 h, higher levels of progesterone were measured in brain and plasma after intranasal than after intraperitoneal delivery. Intranasal progesterone decreased the mortality rate, improved motor functions, reduced infarct, attenuated neuronal loss, and decreased the early BBB disruption. This study demonstrates a good bioavailability, a prolonged absorption and a good neuroprotective efficacy of intranasal delivery of progesterone, thus potentially offering an efficient, safe, non-stressful and very easy mode of administration in stroke patients.

Progesterone is commonly considered as a female reproductive hormone and is well-known for its role in pregnancy. It is less well appreciated that progesterone and its metabolite allopregnanolone are also male hormones, as they are produced in both sexes by the adrenal glands. In addition, they are synthesized within the nervous system. Progesterone and allopregnanolone are associated with adaptation to stress, and increased production of progesterone within the brain may be part of the response of neural cells to injury. Progesterone receptors (PR) are widely distributed throughout the brain, but their study has been mainly limited to the hypothalamus and reproductive functions, and the extra-hypothalamic receptors have been neglected. This lack of information about brain functions of PR is unexpected, as the protective and trophic effects of progesterone are much investigated, and as the therapeutic potential of progesterone as a neuroprotective and promyelinating agent is currently being assessed in clinical trials. The little attention devoted to the brain functions of PR may relate to the widely accepted assumption that non-reproductive actions of progesterone may be mainly mediated by allopregnanolone, which does not bind to PR, but acts as a potent positive modulator of γ-aminobutyric acid type A (GABA(A) receptors. The aim of this review is to critically discuss effects of progesterone on the nervous system via PR, and of allopregnanolone via its modulation of GABA(A) receptors, with main focus on the brain. Fil: Schumacher, M.. Inserm; Francia Fil: Mattern, C.. MetP Pharma AG ; Suiza Fil: Ghoumari, A.. Inserm; Francia Fil: Oudinet, J. P.. Inserm; Francia Fil: Liere, P.. Inserm; Francia Fil: Labombarda, Maria Florencia. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Biología y Medicina Experimental (i); Argentina Fil: Sitruk Ware, Régine. The Rockefeller University; Estados Unidos. Population Council. Center for Biomedical Research ; Estados Unidos Fil: de Nicola, Alejandro Federico. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Biología y Medicina Experimental (i); Argentina Fil: Guennoun, R.. Inserm; Francia

International audience; Lost myelin can be replaced after injury or during demyelinating diseases in a regenerative process called remyelination. In the central nervous system (CNS), the myelin sheaths, which protect axons and allow the fast propagation of electrical impulses, are produced by oligodendrocytes. The abundance and widespread distribution of oligodendrocyte progenitors (OPs) within the adult CNS account for this remarkable regenerative potential. Here, we report a key role for the male gonad, testosterone, and androgen receptor (AR) in CNS remyelination. After lysolecithin-induced demyelination of the male mouse ventral spinal cord white matter, the recruitment of glial fibrillary acidic protein-expressing astrocytes was compromised in the absence of testes and testosterone signaling via AR. Concomitantly, the differentiation of OPs into oligodendrocytes forming myelin basic protein (MBP)(+) and proteolipid protein-positive myelin was impaired. Instead, in the absence of astrocytes, axons were remyelinated by protein zero (P0)(+) and peripheral myelin protein 22-kDa (PMP22)(+) myelin, normally only produced by Schwann cells in the peripheral nervous system. Thus, testosterone favors astrocyte recruitment and spontaneous oligodendrocyte-mediated remyelination. This finding may have important implications for demyelinating diseases, psychiatric disorders, and cognitive aging. The testosterone dependency of CNS oligodendrocyte remyelination may have roots in the evolutionary history of the AR, because the receptor has evolved from an ancestral 3-keto-steroid receptor through gene duplication at the time when myelin appeared in jawed vertebrates.

Withdrawal and avoidance behavior are common symptoms of depression and can appear as a consequence of absence of reward, i.e. extinction-induced depression (EID). This is particularly relevant for the aged organism subjected to pronounced loss of former rewards. Avoidance of the former site of reward and increased withdrawal into a distant compartment accompany extinction of food-rewarded behavior in rodent models. During extinction, behavioral markers for re-learning dissociate from indicators of extinction-induced depression. Here we examined the effect of a chronic treatment with corticosterone (CORT), a well-known inducer of depression-related behavior, on EID in adult and aged rats. Adult (3-4months) and aged (18months) male rats were treated with CORT via drinking water for 3weeks prior to extinction of a cued food-reward task. CORT treatment increased the distance from the site of reward and decreased goal tracking behavior during extinction, especially in the aged rats. Plasma hormone levels measured before and after restraint stress showed a decline in basal ACTH- and CORT-levels after chronic CORT treatment in aged animals. The treatment significantly impaired the HPA-axis activation after acute stress in both, adult and aged animals, alike. Altogether, these findings show an enhancement of EID after chronic CORT treatment in the aged organism, which may be mediated by an impaired HPA-axis sensitivity. These findings may have special relevance for the investigation of human geriatric depression.

The neurosteroid pregnenolone (PREG) has been shown to have memory-enhancing and anti-depressant action. The present study addresses the question of whether intranasally applied pregnenolone (IN-PREG) also has promnestic properties in the rat. We examined the effects of IN-PREG at doses of 0.187 and 0.373mg/kg on memory for objects and their location on learning and retention of escape in a water maze, and on behavior on the elevated plus maze. The main findings were: (a) Pre-trial, but not post-trial, administration of IN-PREG facilitated long-term memory in a novel object-preference test and a novel object-location preference test when tested 48h after dosing. (b) Over the duration of 5days of extinction trials, after learning to escape onto a hidden platform in a water maze, the animals treated with IN-PREG spent more time in searching for the absent platform, indicating either, or both, superior memory for the former position of the escape platform, or a higher resistance to extinction. (c) Administration of the anticholinergic, scopolamine, disrupted learning to escape from the water maze in the vehicle-treated group. The IN-PREG treated groups exhibited superior escape learning in comparison with vehicle controls, indicating that the treatment countered the scopolamine effect. IN-PREG treatment had no influence on behaviors on the elevated plus maze. Our results demonstrate that IN-PREG is behaviorally active with cognitive enhancing properties comparable to those known from studies employing systemic PREG administration.

Reward-dependent instrumental behavior must continuously be re-adjusted according to environmental conditions. Failure to adapt to changes in reward contingencies may incur psychiatric disorders like anxiety and depression. When an expected reward is omitted, behavior undergoes extinction. While extinction involves active re-learning, it is also accompanied by emotional behaviors indicative of frustration, anxiety, and despair (extinction-induced depression). Here, we report evidence for a sphingolipid mechanism in the extinction of behavior. Rapid extinction, indicating efficient re-learning, coincided with a decrease in the activity of the enzyme acid sphingomyelinase (ASM), which catalyzes turnover of sphingomyelin to ceramide, in the dorsal hippocampus of rats. The stronger the decline in ASM activity, the more rapid was the extinction. Sphingolipid-focused lipidomic analysis showed that this results in a decline of local ceramide species in the dorsal hippocampus. Ceramides shape the fluidity of lipid rafts in synaptic membranes and by that way can control neural plasticity. We also found that aging modifies activity of enzymes and ceramide levels in selective brain regions. Aging also changed how the chronic treatment with corticosterone (stress) or intranasal dopamine modified regional enzyme activity and ceramide levels, coinciding with rate of extinction. These data provide first evidence for a functional ASM-ceramide pathway in the brain involved in the extinction of learned behavior. This finding extends the known cellular mechanisms underlying behavioral plasticity to a new class of membrane-located molecules, the sphingolipids, and their regulatory enzymes, and may offer new treatment targets for extinction- and learning-related psychopathological conditions. Sphingolipids are common lipids in the brain which form lipid domains at pre- and postsynaptic membrane compartments. Here we show a decline in dorsal hippocampus ceramide species together with a reduction of acid sphingomyelinase activity during extinction of conditioned behavior in rats. This reduction was associated with expression of re-learning-related behavior, but not with emotional behaviors. Read the Editorial Highlight for this article on page 485.

Progesterone receptors (PR) are expressed throughout the brain. However, their functional significance remains understudied. Here we report a novel role of PR as crucial mediators of neuroprotection using a model of transient middle cerebral artery occlusion and PR knockout mice. Six hours after ischemia, we observed a rapid increase in progesterone and 5-dihydroprogesterone, the endogenous PR ligands, a process that may be a part of the natural neuroprotective mechanisms. PR deficiency, and even haploinsufficiency, increases the susceptibility of the brain to stroke damage. Within a time window of 24 h, PR-dependent signaling of endogenous brain progesterone limits the extent of tissue damage and the impairment of motor functions. Longer-term improvement requires additional treatment with exogenous progesterone and is also PR dependent. The potent and selective PR agonist Nestorone is also effective. In contrast to progesterone, levels of the neurosteroid allopregnanolone, which modulates -aminobutyric acid type A receptors, did not increase after stroke, but its administration protected both wild-type and PR-deficient mice against ischemic damage. These results show that 1) PR are linked to signaling pathways that influence susceptibility to stroke, and 2) PR are direct key targets for both endogenous neuroprotection and for therapeutic strategies after stroke, and they suggest a novel indication for synthetic progestins already validated for contraception. Although allopregnanolone may not be an endogenous neuroprotective agent, its administration protects the brain against ischemicdamageby signaling mechanisms not involving PR. Collectively, our data clarify the relative roles of PR and allopregnanolone in neuroprotection after stroke. Fil: Liu, Ailing. Institut National de la Santé et de la Recherche Médicale; Francia. Université Paris Sud; Francia Fil: Margaill, Isabelle. Institut National de la Santé et de la Recherche Médicale; Francia. Universite de Paris V; Francia. University Paris Descartes; Francia Fil: Zhang, Shaodong. Institut National de la Santé et de la Recherche Médicale; Francia. Université Paris Sud; Francia Fil: Labombarda, Maria Florencia. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Biología y Medicina Experimental. Fundación de Instituto de Biología y Medicina Experimental. Instituto de Biología y Medicina Experimental; Argentina. Universidad de Buenos Aires. Facultad de Medicina. Departamento de Bioquímica Humana; Argentina Fil: Coqueran, Bérard. Institut National de la Santé et de la Recherche Médicale; Francia. Universite de Paris V; Francia Fil: Delespierre, Brigitte. Université Paris Sud; Francia. Institut National de la Santé et de la Recherche Médicale; Francia Fil: Liere, Philippe. Université Paris Sud; Francia. Institut National de la Santé et de la Recherche Médicale; Francia Fil: Marchand Leroux, Catherine. Institut National de la Santé et de la Recherche Médicale; Francia. Universite de Paris V; Francia Fil: O’Malley, Bert W.. Baylor College of Medicine; Fil: Lydon, John P.. Baylor College of Medicine; Fil: de Nicola, Alejandro Federico. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Biología y Medicina Experimental. Fundación de Instituto de Biología y Medicina Experimental. Instituto de Biología y Medicina Experimental; Argentina Fil: Sitruk Ware, Regine. The Rockefeller University; Estados Unidos Fil: Mattern, Claudia. MetP Pharma AG; Suiza Fil: Plotkine, Michel. Universite de Paris V; Francia Fil: Schumacher, Michael. Institut National de la Santé et de la Recherche Médicale; Francia. Université Paris Sud; Francia Fil: Guennoun, Rachida. Université Paris Sud; Francia. Institut National de la Santé et de la Recherche Médicale; Francia

Neurosteroids hold great promise for the treatment of diseases of the central nervous system (CNS). We compared the uptake by 11 brain regions and appearance in blood of tritium-labeled pregnenolone and progesterone after intranasal and intravenous (IV) injection. Both neurosteroids appeared in blood and brain after either method of administration, but with important differences in uptake. Bioavailability based on appearance in arterial serum showed that about 23% and 14% of the intranasal administered doses of pregnenolone and progesterone, respectively, entered the blood. Brain levels were about two fold lower after intranasal administration for the two neurosteroids. With intranasal administration, brain levels of the two steroids did not vary over time (2-120 min), whereas brain levels were higher early (10 min or less) after i.v. administration. With i.v. administration, uptake by brain regions did not vary, whereas the olfactory bulb, hippocampus, and hypothalamus had high uptake rates after intranasal administration. Intranasal administration of prenenolone improved memory, whereas progesterone decreased anxiety, thus demonstrating that therapeutic levels of neurosteroids can be delivered to the brain by intranasal administration. The neurosteroids were rapidly degraded after i.v. or intranasal delivery, but pregnenolone was more resistant to degradation in the brain after intranasal administration and in serum after i.v. administration. These results show that either the i.v. or intranasal routes of administration can deliver neurosteroids to blood and brain, but that the two routes have significant differences with intranasal administration favoring some brain regions.

Contains fulltext : 77294.pdf (Publisher’s version ) (Closed access) Testosterone modulates mood and sexual function in women. However, androgen levels decline with age, which may relate to the age-associated change in sexual functioning and the prevalence of mood and anxiety disorders. These effects of testosterone are potentially mediated by the amygdala. In the present study, we investigated whether the age-related decline in androgen levels is associated with reduced amygdala activity, and whether exogenous testosterone can restore amygdala activity. Healthy young and middle-aged women participated during the early follicular phase of the menstrual cycle, and amygdala responses to biologically salient stimuli were measured with functional magnetic resonance imaging (fMRI). Androgen levels were lower in middle-aged than young women, which was associated with decreased amygdala reactivity. Endogenous testosterone levels correlated positively with amygdala reactivity across the young and middle-aged women. The middle-aged women received a single nasal dose of testosterone in a double-blind, placebo-controlled, crossover manner, which rapidly increased amygdala reactivity to a level comparable to the young women. The enhanced testosterone levels correlated positively with superior frontal cortex responses and negatively with orbitofrontal cortex responses across individuals, which may reflect testosterone-induced changes in amygdala regulation. These results show that testosterone modulates amygdala reactivity in women, and suggest that the age-related decline in androgen levels contribute to the decrease in amygdala reactivity.

We evaluated the effects of intranasal administration of progesterone (PROG) on the activity of dopaminergic neurons in the brain of anesthetized rats by means of microdialysis. Male Wistar rats were implanted with guide cannulae in the basolateral amygdala and neostriatum. Three to 5 days later, they were anesthetized with urethane, and dialysis probes were inserted. After a stabilization period of 2 h, four 30-min samples were collected. Thereafter, the treatment (0.5, 1.0 or 2.0 mg/kg of PROG dissolved in a viscous castor oil mixture, or vehicle) was applied into the nose in a volume of 10 microl (5 microl in each nostril). In other animals, an s.c. injection of PROG (1.0, 2.0 or 4.0 mg/kg) or vehicle was given. Samples of both application ways were collected at 30-min interval for 4 h after the treatment and immediately analyzed with high performance liquid chromatography and electrochemical detection. Intranasal administration of 2 mg/kg of PROG led to an immediate (within 30 min after the treatment) significant increase in the basolateral amygdala dopamine levels. In the neostriatum, the 2 mg/kg dose led to a delayed significant increase in dopamine. S.c. administration of 4 mg/kg of PROG was followed by a delayed significant increase in dopamine, both, in the basolateral amygdala and neostriatum, but smaller in magnitude in comparison to the intranasal treatment. This is the first study to demonstrate dopamine-enhancing effects of PROG, not only in the neostriatum, but also in the basolateral amygdala. Our results indicate that the intranasal route of administration of PROG is a more efficacious way for targeting the brain than the s.c. route.

Although multiple forms of testosterone replacement therapy are available to treat hypogonadism, none is ideal. This article reports on the pharmacokinetics of an innovative nasal formulation of testosterone in hypogonadal men. The first study was undertaken in eight men with a baseline total testosterone (TT) of 130.8 +/- 87.4 ng/dL and examined the pharmacokinetics of nasal testosterone given in a single dose of 7.6 mg, 15.2 mg or 22.8 mg, respectively. The second study examined the pharmacokinetics of nasal testosterone (7.6 mg) given either twice or three times a day in 21 severely hypogonadal men (baseline TT in 20 patients50 ng/dL, in one patient 152 ng/dL) for 14 days. The steady-state concentration of testosterone was within the normal range in all treatment groups, but only in the 3-times-a-day group was the 95% confidence interval completely within the physiological range. The average DHT level did not exceed the upper range of normal. The clinical global visual analogue scale improved in the whole group receiving testosterone (p0.001). All adverse events in both studies were of mild to moderate intensity and were evaluated as unlikely or not related to the administered study drug. No patients dropped out during treatment. Comparison with the normal circadian rhythm by computer modelling suggests that nasal testosterone can be used to mimic the normal diurnal pattern in eugonadal men. Thus, nasal testosterone can be administered safely to humans in doses that approximate serum concentrations in the normal physiological range.

Background: Recently, we found evidence that intra-nasally administered dopamine (DA), can enter the brain, leading to an immediate increase in extracellular DA levels in striatal subregions. This offers a potential alternative approach to target the brain with exogenous DA, which otherwise cannot cross the blood-brain barrier. Here, we examined whether intra-nasally applied DA also exerts behavioral activity on mesocortical and nigrostriatal dopaminergic functions. Method: Male Wistar rats (3–4 months) were tested for potential behavioral effects of intra-nasally applied DA (0.03, 0.3 or 3.0 mg/kg) in the forced swimming test (FST) for antidepressant-like activity, elevated plus-maze for anxiety-related behavior, and on motor activity in a novel and familiar environment. Results: Intra-nasally administered dopamine in a dose of 0.3 mg/kg exerted antidepressant-like activity in the FST, but had neither anxiolytic-like nor anxiogenic-like effects in the elevated plus-maze. Furthermore, intra-nasal dopamine stimulated locomotor activity in a familiar, but not novel, open field. Conclusions: These results support the view that intra-nasally applied DA can act on the central nervous system by entering the brain via the nose-brain pathway, making this kind of application procedure a promising alternative for targeting the brain, and thus treating disorders involving mesocortical and/or nigrostriatal dopaminergic disturbances.

Dopamine (DA) plays an important role in a number of behavioral processes and neurological disorders. The intranasal administration of DA provides improved brain penetrability in comparison to systemic administration. We investigated the effects of intranasal administration of DA on the activity of dopaminergic neurons of the mesostriatal and mesolimbic systems and on motor activity. Rats previously implanted with guide-cannulae in the neostriatum (NS) and nucleus accumbens (NAc) were submitted to microdialysis procedure under urethane anesthesia. Vehicle or DA (0.03, 0.3, or 3.0 mg/kg) was administered bilaterally into the nostrils. In a separate study, animals received an intraperitoneal (i.p.) injection of vehicle or DA (0.03, 0.3, 3.0, or 30.0 mg/kg). Samples were collected every 10 min and analyzed for the content of DA and metabolites using high-performance liquid chromatography. For the open field study, rats were given intranasal vehicle or DA (0.03, 0.3, or 3.0 mg/kg) and placed into the field for 30 min. Motor activity (locomotion and rearing) and grooming were analyzed in blocks of 10 min using Ethovision. Intranasal DA (3.0 mg/kg) significantly increased DA levels in the NS and NAc immediately after administration. A comparable effect was obtained only after i.p. administration of 30 mg/kg DA. In the open field, the 3.0 mg/kg dose significantly decreased grooming behavior in the second 10 min interval and significantly increased locomotor activity in the third 10 min interval. The data indicate that intranasal administration of DA can influence dopaminergic functions and motor activity, and has a potential application in the therapy of diseases affecting the dopaminergic system. Synapse 62:176–184, 2008. © 2007 Wiley-Liss, Inc.

Sexual dysfunction in the female has been associated with a decrease in androgen levels, which can be reversed by testosterone treatment, however, bearing the risk of adverse side effects. Previously we found that intranasal application of testosterone led to an increase in proceptive behavior in female capuchin monkeys, which was still enhanced beyond treatment pointing to prolonged effects. Here, we sought to replicate our previous findings and to further examine possible prolonged effects of such treatment. During 5 days of baseline females were observed for their sexual and non-sexual behavior without drug. They then received daily intranasal testosterone (0.24 mg per nostril) for 7 days, followed by 15 days of intranasal testosterone application every third day or were left undisturbed (n = 5 per group). Diverse sexual and non-sexual behaviors were scored. Blood samples were collected and analyzed for testosterone, estradiol, and progesterone using immunoenzymatic chemiluminescent immunoassay. In accord with our previous results an increase in sexual proceptive behavior was revealed during testosterone treatment, which persisted about 2 weeks beyond treatment in the group receiving testosterone every third day as well as in the group that no longer received any treatment. These behavioral results were accompanied by an increase in plasma testosterone levels. This study demonstrates the efficacy of testosterone in enhancing sexual behavior in female capuchin monkeys by means of intranasal application, and provided evidence that daily substance application is not necessary to maintain beneficial effects on sexual behavior. These findings render the intranasal application procedure to be a useful alternative compared to other forms of administration.

This study investigated the effect of intranasal administration of progesterone on the early brain mitochondrial respiratory chain dysfunction and oxidative damage after transient middle cerebral occlusion in male and female mice. We showed that progesterone (8 mg/kg at 1 h post-middle cerebral occlusion) restored the mitochondrial reduced glutathione pool and the nicotinamide adenine dinucleotide-linked respiration in both sexes. Progesterone also reversed the decrease of the flavin adenine dinucleotide-linked respiration, which was only observed in females. Our findings point to a sex difference in stroke effects on the brain respiratory chain and suggest that the actions of progesterone on mitochondrial function may participate in its neuroprotective properties.

Intranasal application of dopamine (IN-DA) has been shown to increase motor activity and to release DA in the ventral (VS) and dorsal striatum (DS) of rats. The aim of the present study was to assess the effects of IN-DA treatment on parameters of DA and excitatory amino acid (EEA) function in prepuberal rats of the Naples High Excitability line (NHE), an animal model for attention-deficit hyperactivity disorder and normal random-bred (NRB) controls. Methods: NHE and NRB rats were daily administered INDA (0.075, 0.15, 0.30 mg/kg) or vehicle for 15 days from postnatal day 28 to 42 and subsequently tested in the Làt maze and in the eight arm radial Olton maze. Soluble Powered by Editorial Manager® and ProduXion Manager® from Aries Systems Corporation and membrane-trapped L-Glutamate (L-Glu) and L-Aspartate (L-Asp) levels as well as NMDAR1 subunit protein levels were determined post mortem in IN-DA- and vehicletreated NHE and NRB rats in prefrontal cortex (PFc), DS and VS. Moreover DA transporter (DAT) protein and tyrosine hydroxylase (TH) levels were assessed in PFc, DS, VS and mesencephalon (MES) and in ventral tegmental area and substantia nigra, respectively. Results: In NHE rats, IN-DA (0.30mg/kg) decreased horizontal activity and increased non-selective attention relative to vehicle, whereas the lower dose (0.13 mg/kg) increased selective spatial attention. In NHE rats, basal levels of soluble EEAs were reduced in PFc and DS relative to NRB controls, while membrane-bound EEAs were elevated. Moreover, basal NMDAR1 subunit protein levels were increased in PFc, DS and VS relative to NRB controls. Also DAT protein levels were elevated in PFc, VS and MES relative to NRB controls. IN-DA led to a number of changes of EAA, NMDRR1 subunit protein, TH and DAT protein levels in PFc, DS, VS, MES and VTA, in both NHE and NRB rats with significant differences between strains. Conclusions: Our findings indicate that the NHE rat model of ADHD may be characterized by (1) prefrontal and striatal DAT hyperfunction, indicative of DA hyperactivty, and (2) prefrontal and striatal NMDA receptor hyperfunction indicative of net EAA hyperactivty. IN-DA had ameliorative effects on activity level, attention, and working memory, which are likely to be associated with DA action at inhibitory D2 autoreceptors, leading to a reduction of striatal DA hyperactivity and, possibly, DA action striatal EAA levels, leading to a reduction of striatal EAA hyperfunction (with persistence of prefrontal EAA hyperfunction). Previous studies on IN-DA treatment in rodents have indicated antidepressant, anxiolytic and anti-parkinsonian effects in relation to enhanced central dopaminergic activity. Our present results strengthen the prospects of potential therapeutic applications of intranasal application of dopamine by indicating also an enhancement of selective attention and working memory in a deficit model.

L-DOPA provides the most potent medication to treat Parkinson's disease, and such systemic treatment is usually combined with a peripheral amino acid decarboxylase inhibitor to amplify its central effectiveness. Since L-DOPA can lose its efficacy or can lead to adverse effects with prolonged application, current pharmacokinetic and dynamic research is aimed at improving the drug's applicability. In a previous study, performed with in vivo microdialysis in the anesthetized rat, we have shown that intranasal L-DOPA administration (without prior decarboxylase inhibition) can increase extracellular dopamine levels in the neostriatum. Using similar experimental conditions in the present experiment, we tested the neurochemical effects of L-DOPA treatment in combination with the peripheral amino acid decarboxylase inhibitor benserazide. In accordance with other data, it was found that the combination of i.p. benserazide and i.p. L-DOPA led to pronounced increases of extracellular levels of dopamine, dihydroxyplenylacetic acid and homovanillic acid in the neostriatum, whereas i.p. L-DOPA alone only moderately increased dopamine, but strongly increased the metabolite levels. Furthermore, increased dopamine levels, and weaker increases of dihydroxyplenylacetic acid and homovanillic acid were observed after i.p. benserazide followed by intranasal L-DOPA. Finally, we found that i.p. benserazide alone can lead to pronounced increases in neostriatal dopamine and moderate increases of dihydroxyplenylacetic acid levels, whereas it did not affect homovanillic acid. Thus, not only the combination of L-DOPA (i.p. or intranasal) with the presumed peripheral L-DOPA decarboxylase inhibitor benserazide, but also each component alone can affect dopamine activity in the brain. Especially the findings with benserazide treatment might be of relevance for understanding the mechanisms of current L-DOPA therapy, since they indicate that part of the treatment's actions may possibly be determined by central dopaminergic effects of the accompanying amino acid decarboxylase inhibitor. Synapse 27:294–302, 1997. © 1997 Wiley-Liss, Inc.

The effects of the known anxiolytic compound diazepam (DZ) on the behavior of rats in the elevated plus-maze were compared with those of zingicomb (ZC) (registered trademark of Mattern et Partner), a combination preparation of standardized extracts of Ginkgo biloba and Zingiber officinale. DZ was administered intraperitoneally (IP) in a reference dosage of 1 mg/kg 30 min before the rats were tested on the elevated plus-maze for 5 min. The treatment with DZ elevated the time spent on the open arms and excursions into the end of the open arms, increased scanning over the edge of an open arm, and decreased risk-assessment from an enclosed arm. ZC was administered intragastrically (IG) in four doses ranging between 0.5 and 100 mg/kg 60 min prior to plus-maze testing. The treatment with 0.5 mg/kg ZC elevated the time spent on the open arms and excursions into the end of the open arms; at the high dosage of 100 mg/kg, ZC led to fewer excursions to and less scanning of the open arms. Injection of 1 or 10 mg/kg ZC had no significant effect on the behavior in the maze. These data provide evidence that ZC has anxiolytic effects in the elevated plus-maze comparable to those of DZ, but that in high dosage the phytopharmacon may also have anxiogenic properties. The anxiolytic-like effects of ZC are discussed with regard to the known antiserotonergic action of ginger and Ginkgo biloba.

Progesterone is well known as a female reproductive hormone and in particular for its role in uterine receptivity, implantation, and the maintenance of pregnancy. However, neuroendocrine research over the past decades has established that progesterone has multiple functions beyond reproduction. Within the nervous system, its neuromodulatory and neuroprotective effects are much studied. Although progesterone has been shown to also promote myelin repair, its influence and that of other steroids on myelination and remyelination is relatively neglected. Reasons for this are that hormonal influences are still not considered as a central problem by most myelin biologists, and that neuroendocrinologists are not sufficiently concerned with the importance of myelin in neuron functions and viability. The effects of progesterone in the nervous system involve a variety of signaling mechanisms. The identification of the classical intracellular progesterone receptors as therapeutic targets for myelin repair suggests new health benefits for synthetic progestins, specifically designed for contraceptive use and hormone replacement therapies. There are also major advantages to use natural progesterone in neuroprotective and myelin repair strategies, because progesterone is converted to biologically active metabolites in nervous tissues and interacts with multiple target proteins. The delivery of progesterone however represents a challenge because of its first-pass metabolism in digestive tract and liver. Recently, the intranasal route of progesterone administration has received attention for easy and efficient targeting of the brain. Progesterone in the brain is derived from the steroidogenic endocrine glands or from local synthesis by neural cells. Stimulating the formation of endogenous progesterone is currently explored as an alternative strategy for neuroprotection, axonal regeneration, and myelin repair.

Contains fulltext : 89046.pdf (Publisher’s version ) (Closed access) Testosterone influences various aspects of affective behavior, which is mediated by different brain regions within the emotion circuitry. Previous neuroimaging studies have demonstrated that testosterone increases neural activity in the amygdala. To investigate whether this could be due to altered regulation of amygdala functioning which is thought to be mediated by the prefrontal cortex, we studied the effects of exogenous testosterone on the interaction between the amygdala and other brain regions. Healthy middle-aged women received a single nasal testosterone dose in a randomized, placebo-controlled, crossover manner, and performed an emotional face matching task while their brain activity was measured with functional MRI. The results show that testosterone rapidly reduced functional coupling of the amygdala with the orbitofrontal cortex, and enhanced amygdala coupling with the thalamus. This suggests that testosterone may reduce the regulatory control over the amygdala, or that testosterone shifts amygdala output away from the orbitofrontal cortex towards the thalamus. Testosterone also reduced functional coupling with the contralateral amygdala. Because interhemispheric amygdala coupling is lower in men than in women, this result suggests that circulating testosterone may contribute to this sexual dimorphism. 01 januari 2010

Due to its lipophobic properties, dopamine is unable to cross the blood–brain barrier following systemic application. However, recently it has been demonstrated that, when applied directly via the nasal passages in the rat, dopamine exerts neurochemical and behavioural action, including increases of dopamine in striatal subregions, antidepressive-like action, and increased behavioral activity. These effects could potentially be mediated by exogenous dopamine acting as a direct agonist at postsynaptic dopamine receptors. However, it is also possible that intranasally applied dopamine acts indirectly via the modulation of the activity of dopaminergic cell bodies. To approach this question, the present study used rats with unilateral 6-hydroxydopamine (6-OHDA) lesions of the nigrostriatal tract, as these lesions lead to pharmacologically stimulated behavioural asymmetries which are specific for direct and indirect dopamine agonists. We found that 7 days of repeated treatment with intranasal dopamine induced a sensitization of the turning response to amphetamine, but not to apomorphine. Furthermore, intranasal dopamine dose-dependently increased the use of the forepaw ipsilateral to the 6-OHDA-lesioned side of the brain. These results suggest that intranasally administered dopamine acts via an indirect mechanism of action, putatively by increasing the release of endogenous dopamine in the brain.

Intranasal (i.n.) administration has emerged as a strategy to deliver therapeutics to the brain. Here, we compared i.n. and intravenous (i.v.) administration for testosterone. About 75% of the i.n. administered testosterone entered the blood. However, whole brain levels of testosterone were about twice as high after i.n. administration as after i.v. administration. About two-thirds of the testosterone entering the brain after i.n. administration did so by direct entry by nasal routes and the remainder indirectly by first entering the blood and then crossing the blood-brain barrier. All brain regions except the frontal cortex had higher levels of testosterone after i.n. administration than after i.v. administration, although the differences among brain regions varied much more for the i.n. route. The olfactory bulb, hypothalamus, striatum, and hippocampus had the highest levels after i.n. administration. The brain uptake pattern suggested a variety of distribution routes likely involving the cerebrospinal fluid, diffusion through brain tissue, and transport through nerve projections. Regional distribution patterns were similar after either i.n. or i.v. administration, suggesting that the dominant factor determining distribution/retention was the same for either route of administration. We conclude that the i.n. administration route delivers testosterone systemically and can target the brain, especially the olfactory bulb, hypothalamus, striatum, and hippocampus.

Testosterone was administered intranasally in anesthetized male rats, and its effects on the activity of dopaminergic and serotonergic neurons in the neostriatum and nucleus accumbens were assessed by means of microdialysis and HPLC. The treatment (0.5, 1.0 or 2.0 mg/kg of testosterone or vehicle, 10 microl volume) was applied in both nostrils, half (5 microl) into each. Subcutaneous injections of testosterone (2.0, 4.0 or 8.0 mg/kg) or vehicle were tested in other subjects. Samples were collected for 5 h. In the neostriatum, an increase of dopamine occurred after 2.0 mg/kg. Serotonin levels increased after 1.0 mg/kg dose. In the nucleus accumbens, dopamine and serotonin increased after 1.0 mg/kg and 2.0 mg/kg doses. Subcutaneous administration of 8.0 mg/kg testosterone increased dopamine and serotonin in the neostriatum only. We conclude that intranasal administration of testosterone is a more efficacious way for targeting the brain than the subcutaneous route, and may be considered as a means to activate central dopaminergic and serotonergic systems.

Contains fulltext : 115458.pdf (Publisher’s version ) (Closed access) Female mate choice involves the comparative evaluation of potential mates. Females use a pooled comparison of sampled males to maximize the perceived reproductive fitness of their partner, implying the memorization of sampled males. However, hormonal and reproductive states influence female choosiness, and women's preference and memory for masculinity. Here, we investigated whether testosterone biases memory processes in women towards male faces using functional MRI. A single nasal testosterone dose was administered to healthy women in their early follicular phase, in a double-blind, placebo-controlled, crossover design. Testosterone increased the difference in reaction times to categorize male and female faces during encoding, without influencing subsequent recognition accuracy or response bias. The imaging results showed that testosterone shifted memory formation in the hippocampus and inferior temporal gyri from the encoding of female faces towards the encoding of male faces. In contrast, testosterone shifted memory formation in the left inferior frontal gyrus from the encoding of male faces towards the encoding of female faces. Furthermore, the hippocampal contribution to memory retrieval also shifted from female towards male faces. These results indicate that testosterone biases memory processes towards the relatively automatic encoding and retrieval of males in temporal brain regions and elaborate encoding of females in frontal brain regions, suggesting that testosterone may support female mate sampling and comparison by biasing automatic memory processes towards the encoding and retrieval of potential mates.

Sexual dysfunction in the female has been associated with a decrease in androgen levels, which can be reversed by testosterone treatment, however, bearing the risk of adverse side effects. Nasally administered testosterone could be an effective method for androgenic treatment avoiding the first-pass intestinal and hepatic metabolism and side effects. Here we examined the effects of chronic intranasal administration of testosterone on sexual behavior in female capuchin monkeys (Cebus apella) that lived with male cohorts. During 8 days of baseline 10 females were observed for their sexual and non-sexual behavior without drug. They then received daily intranasal testosterone (0.24 mg per nostril, n = 5 per group) or placebo gel for 5 days, followed by 5 days of wash out, followed by 5 days of daily intranasal application, whereby the animals that had received testosterone before, now received placebo and vice versa. Diverse sexual and non-sexual behaviors were scored. Blood samples were collected and analyzed for testosterone, estradiol, dihydrotestosterone and progesterone using EIAs. The results revealed an increase in sexual behavior (eyebrow raising, chest rubbing, courtship behavior, masturbation) in the females during testosterone treatment, which seemed to be prolonged even when testosterone treatment was discontinued. These behavioral results were accompanied by an increase in plasma testosterone levels. This study demonstrates the efficacy of testosterone in enhancing sexual behavior in female capuchin monkeys by means of intranasal application, which may be a useful alternative compared to other forms of administration.

Here we assessed the effects of i.g. administration of Zingicomb (ZC), a mixture of zingiber officinale and ginkgo biloba extracts, on learning and memory, and on indicators of oxidative stress in aged rats. Effects of ZC (1 and 10 mg/kg) were investigated in 22-24 months old Wistar rats using the Morris water maze, in which they show deficient performance as compared to 3 months old rats in the undrugged state (days 1 and 2). Treatment was administered on days 3 and 4 of training, then over 7 days with training discontinued, and again on days 5 and 6 when training was resumed. Thereafter chronic treatment was maintained over 5 months. 1 mg/kg ZC improved escape learning in the water maze. The two capital indicators of oxidative stress in brain homogenates, the amount of oxidized proteins (assessed as carbonyl group containing proteins) and lipid peroxidation, were significantly reduced in ZC treated animals. Thus, ZC, which had previously been shown to improve inhibitory avoidance learning and to have anxiolytic properties in adult animals, might also facilitate spatial learning in aged animals, and reduces indices of oxidative stress in brain tissue after chronic treatment.

HASENOHRL, R. U., B. TOPIC, C. FRISCH, R. HACKER, C. M. MATTERN AND J. P. HUSTON. Dissociation between anxiolytic and hypomnestic effects for combined extracts of zingiber officinale and ginkgo biloba, as opposed to diazepam. PHARMACOL BIOCHEM BEHAV 59 (2) 527–535, 1998.—Previous work has shown that Zingicomb ® (ZC), a combination preparation of zingiber officinale and ginkgo biloba, exerts anxiolytic-like effects in the elevated plus-maze (EPM), possibly related to 5-HT antagonistic properties of its components. The first experiment of this study was performed to gauge the specificity of the anxiolytic action of ZC with respect to the mixture ratio of the single components in the combination preparation. Two different combinations of zingiber officinale and ginkgo biloba extracts (ratio of components: 1:1 or 1:2.5) were compared with the standard ratio adjusted for ZC (2.5:1). Each combination was administered intragastrically (IG) in five doses (0.01 to 10 mg/kg) before the rats were tested on the EPM. Zingicomb at 1 mg/kg elevated the time spent on the open arms, scanning of the open arms and excursions into the ends of the open arms, whereas the two other combinations (1:1 and 1:2.5) did not influence rats’ behavior on the EPM in the entire dose range tested. With regard to the memory-disrupting effects of anxiolytics, particularly of diazepam (DZP), a second experiment was performed to compare the effects of ZC (0.5, 1, 10 mg/kg, IG) and DZP (1 or 5 mg/kg, IP) on the performance of rats in two different learning tasks. Rats were treated with DZP or ZC prior to the learning trial of a one-trial step-through inhibitory avoidance task. Retention testing 24 h later showed impaired retention for rats injected with DZP at 5 mg/kg but not for animals that had received ZC prior to training. In a further experiment, rats were treated once daily with DZP or ZC prior to the training trials in a water maze. Injections of DZP at 5 mg/kg impaired place and cue learning, whereas the treatment with ZC did not influence the navigation performance in the maze. The present results indicate that the anxiolytic-like effects of ZC are specific in that only the mixture ratio of zingiber officinale and ginkgo biloba adjusted for the phytopharmacon was active in the EPM. Furthermore, ZC did not interfere negatively with the performance on an inhibitory avoidance and a water maze task, as opposed to DZP. This finding is interesting with regard to other studies that have revealed a similar dissociation between anxiolytic and memory-disrupting effects for chemically defined 5-HT antagonists, especially for those acting at 5-HT 3 receptors.