Suchergebnisse

Anxiety disorders are often associated with an inability to extinguish learned fear responses. The hypocretin/orexin system is involved in the regulation of emotional states and could also participate in the consolidation and extinction of aversive memories. Using hypocretin receptor-1 and hypocretin receptor-2 antagonists, hypocretin-1 and hypocretin-2 peptides, and hypocretin receptor-1 knockout mice, we investigated the role of the hypocretin system in cue- and context-dependent fear conditioning and extinction. Hypocretins were crucial for the consolidation of fear conditioning, and this effect was mainly observed in memories with a high emotional component. Notably, after the acquisition of fear memory, hypocretin receptor-1 blockade facilitated fear extinction, whereas hypocretin-1 administration impaired this extinction process. The extinction-facilitating effects of the hypocretin receptor-1 antagonist SB334867 were associated with increased expression of cFos in the basolateral amygdala and the infralimbic cortex. Intra-amygdala, but neither intra-infralimbic prefrontal cortex nor intra-dorsohippocampal infusion of SB334867 enhanced fear extinction. These results reveal a key role for hypocretins in the extinction of aversive memories and suggest that hypocretin receptor-1 blockade could represent a novel therapeutic target for the treatment of diseases associated with inappropriate retention of fear, such as post-traumatic stress disorder and phobias. ; This work was supported by the Instituto de Salud Carlos III grants, #PI13/00042 and #RD12/0028/0023 (RTA-RETICS), by the Spanish Ministry of Science #SAF2011-29864, the/nCatalan Government (SGR2009-00731), and by the Catalan Institution for Research and Advanced Studies (ICREA Academia program). África Flores is a recipient of a predoctoral fellowship from the Spanish Ministry of Education.

Food palatability produces behavioral modifications that resemble those induced by drugs of abuse. Palatability-induced behavioral changes require both, the activation of the endogenous cannabinoid system, and changes in structural plasticity in neurons of the brain reward pathway. The ERK intracellular pathway is activated by CB1 receptors (CB1-R) and plays a crucial role in neuroplasticity. We investigated the activation of the ERK signaling cascade in the mesocorticolimbic system induced by operant training to obtain highly palatable isocaloric food and the involvement of the CB1-R in these responses. Using immunofluorescence techniques, we analyzed changes in ERK intracellular pathway activation in the mesocorticolimbic system of wild-type and CB1 knockout mice (CB1-/-) trained on an operant paradigm to obtain standard, highly caloric or highly palatable isocaloric food. Operant training for highly palatable isocaloric food, but not for standard or highly caloric food, produced a robust activation of the ERK signaling cascade in the same brain areas where this training modified structural plasticity. These changes induced by the operant training were absent in CB1-/-. We can conclude that the activation of the ERK pathway is associated to the neuroplasticity induced by operant training for highly palatable isocaloric food and might be involved in CB1-R mediated alterations in behavior and structural plasticity. ; This work was supported by the Spanish "Ministerio de Ciencia e Innovación" (#SAF2007-64062 and #SAF2008-00962), "Instituto de Salud Carlos III" (#RD06/001/001), "Plan Nacional sobre Drogas, the Catalan Government" (SGR2009-00131 and SGR 2009-224), the "ICREA Foundation" (ICREA Academia-2008), the "DG Research of the European Commission" (GENADDICT, #LSHM-CT-2004-05166; and PHECOMP, #LSHM-CT-2007-037669) the "FIS" (PI07/0715), "ATIP-Avenir" and "Sanofi-Aventis" grants. This work was also supported by the "Plan Nacional Sobre Drogas" (#2009/026) to R.M

Obesity represents an important risk factor contributing to the global burden of disease. The current obesogenic environment with easy access to calorie-dense foods is fueling this obesity epidemic. However, how these foods contribute to the progression of feeding behavior changes that lead to overeating is not well understood and needs systematic assessment. Using novel automated methods for the high-throughput screening of behavior, we here examine mice meal pattern upon long-term exposure to a free-choice chocolate-mixture diet and a high-fat diet with face validity for a rapid development of obesity induced by unhealthy food regularly consumed in our societies. We identified rapid diet-specific behavioral changes after exposure to those high-caloric diets. Mice fed with high-fat chow, showed long-lasting meal pattern disturbances, which initiate with a stable loss of circadian feeding rhythmicity. Mice receiving a chocolate-mixture showed qualitatively similar changes, though less marked, consisting in a transient disruption of the feeding behavior and the circadian feeding rhytmicity. Strikingly, compulsive-like eating behavior is triggered immediately after exposure to both high-fat food and chocolate-mixture diet, well before any changes in body weight could be observed. We propose these changes as behavioral biomarkers of prodromal states of obesity that could allow early intervention. ; The laboratory of M.D. is supported by DIUE de la Generalitat de Catalunya (Grups consolidats SGR 2014/1125). This work was supported by Fondation Jérôme Lejeune (Paris, France), MINECO (SAF2013‐49129‐C2‐1‐R; SAF2016‐79956‐R), CDTI ('Smartfoods') and EU (Era Net Neuron PCIN‐2013‐060) and the Catalan foundation 'La Marató de TV3' (#2016/20‐30). The CRG is a Center of Excellence Severo Ochoa SEV‐2012‐0208. The CIBER of Rare Diseases is an initiative of the ISCIII. The laboratory of C.N. acknowledge the funding from the Spanish Ministry of Economy and Finance (MINECO), grant number BFU2011‐28575. J.E. received the FI grant from Agència de Gestió d'Ajuts Universitaris i de Recerca (AGAUR) de la Generalitat de Catalunya. The laboratory of R.M. was supported by the DG Research of the European Commission FP7 (#HEALTH‐F2 2013‐602891 and PHECOMP #LHSM‐CT‐2007‐037669), the Spanish 'RETICS‐Instituto de Salud Carlos III' (#RD16/0017/0020), the Spanish 'Ministerio de Economia y Competitividad' (#SAF‐2014‐59648P), the 'Plan nacional sobre drogas' (#PNSD‐2013‐5068), the Catalan Government 'AGAUR‐Generalitat de Catalunya' (#2014‐SGR‐1547) and the Catalan foundation 'La Marató de TV3' (#2016/20‐30).

Background: Neuropathic pain is a complex condition characterized by sensory, cognitive and affective symptoms that magnify the perception of pain. The underlying pathogenic mechanisms are largely unknown and there is an urgent need for the development of novel medications. The endocannabinoid system modulates pain perception and drugs targeting the cannabinoid receptor type 2 (CB2) devoid of psychoactive side effects could emerge as novel analgesics. An interesting model to evaluate the mechanisms underlying resistance to pain is the fragile X mental retardation protein knockout mouse (Fmr1KO), a model of fragile X syndrome that exhibits nociceptive deficits and fails to develop neuropathic pain. Methods: A partial sciatic nerve ligation was performed to wild-type (WT) and Fmr1KO mice having (HzCB2 and Fmr1KO-HzCB2, respectively) or not (WT and Fmr1KO mice) a partial deletion of CB2 to investigate the participation of the endocannabinoid system on the pain-resistant phenotype of Fmr1KO mice. Results: Nerve injury induced canonical hypersensitivity in WT and HzCB2 mice, whereas this increased pain sensitivity was absent in Fmr1KO mice. Interestingly, Fmr1KO mice partially lacking CB2 lost this protection against neuropathic pain. Similarly, pain-induced depressive-like behaviour was observed in WT, HzCB2 and Fmr1KO-HzCB2 mice, but not in Fmr1KO littermates. Nerve injury evoked different alterations in WT and Fmr1KO mice at spinal and supra-spinal levels that correlated with these nociceptive and emotional alterations. Conclusions: This work shows that CB2 is necessary for the protection against neuropathic pain observed in Fmr1KO mice, raising the interest in targeting this receptor for the treatment of neuropathic pain. Significance: Neuropathic pain is a complex chronic pain condition and current treatments are limited by the lack of efficacy and the incidence of important side effects. Our findings show that the pain-resistant phenotype of Fmr1KO mice against nociceptive and emotional manifestations triggered by persistent nerve damage requires the participation of the cannabinoid receptor CB2, raising the interest in targeting this receptor for neuropathic pain treatment. Additional multidisciplinary studies more closely related to human pain experience should be conducted to explore the potential use of cannabinoids as adequate analgesic tools. ; This work was supported by research grants from the Spanish Ministry of Science and Innovation (#SAF2017-84060-R-AEI/FEDER-UE), the European Commission-DG Research (PainFact, #H2020-SC1-2019-2-RTD-848099), the Instituto de Salud Carlos III-RETICS (RTA, #RD16/0017/0020), the Spanish Ministerio de Sanidad, Servicios Sociales e Igualdad-Plan Nacional Sobre Drogas (#PNSD-2017I068) to RM; and the Catalan Government-AGAUR (#SGR2017-669 and ICREA Academia Award 2015 to RM and SGR2017-138 to RdlT). AR-L is the recipient of a FI predoctoral fellowship (Generalitat de Catalunya-AGAUR).

Brain electrical stimulation techniques take advantage of the intrinsic plasticity of the nervous system, opening a wide range of therapeutic applications. Vagus nerve stimulation (VNS) is an approved adjuvant for drug-resistant epilepsy and depression. Its non-invasive form, auricular transcutaneous VNS (atVNS), is under investigation for applications, including cognitive improvement. We aimed to study the effects of atVNS on brain connectivity, under conditions that improved memory persistence in CD-1 male mice. Acute atVNS in the cymba conchae of the left ear was performed using a standard stimulation protocol under light isoflurane anesthesia, immediately or 3 h after the training/familiarization phase of the novel object-recognition memory test (NORT). Another cohort of mice was used for bilateral c-Fos analysis after atVNS administration. Spearman correlation of c-Fos density between each pair of the thirty brain regions analyzed allowed obtaining the network of significant functional connections in stimulated and non-stimulated control brains. NORT performance was enhanced when atVNS was delivered just after, but not 3 h after, the familiarization phase of the task. No alterations in c-Fos density were associated with electrostimulation, but a significant effect of atVNS was observed on c-Fos-based functional connectivity. atVNS induced a clear reorganization of the network, increasing the inter-hemisphere connections and the connectivity of locus coeruleus. Our results provide new insights into the effects of atVNS on memory performance and brain connectivity extending our knowledge of the biological mechanisms of bioelectronics in medicine. ; The project that gave rise to these results received the support of a fellowship from la Caixa Foundation (ID 100010434). The fellowship code is LCF/BQ/IN18/11660012 (CB-P). This project has received funding from the European Union's Horizon 2020 research and innovation program under the Marie Slodowska-Curie grant agreement No. 713673. This work was supported by ...

Hypocretin/orexin signaling is critically involved in relapse to drug-seeking behaviors. In this study, we investigated the involvement of the hypocretin system in the reinstatement of nicotine-seeking behavior induced by nicotine-associated cues. Pretreatment with the hypocretin receptor-1 antagonist SB334867, but not with the hypocretin receptor-2 antagonist TCSOX229, attenuated cue-induced reinstatement of nicotine-seeking, which was associated with an activation of hypocretin neurons of the lateral and perifornical hypothalamic areas. In addition, relapse to nicotine-seeking increased the phosphorylation levels of GluR2-Ser880, NR1-Ser890, and p38 MAPK in the nucleus accumbens (NAc), but not in the prefrontal cortex. Notably, phosphorylation levels of NR1-Ser890 and p38 MAPK, but not GluR2-Ser880, were dependent on hypocretin receptor-1 activation. The intra-accumbens infusion of the protein kinase C (PKC) inhibitor NPC-15437 reduced nicotine-seeking behavior elicited by drug-paired cues consistent with the PKC-dependent phosphorylations of GluR2-Ser880 and NR1-Ser890. SB334867 failed to modify cue-induced reinstatement of food-seeking, which did not produce any biochemical changes in the NAc. These data identify hypocretin receptor-1 and PKC signaling as potential targets for the treatment of relapse to nicotine-seeking induced by nicotine-associated cues. ; This work was supported by the Instituto de Salud Carlos III grants, #PI07/0559, #PI10/00316 and #RD06/001/001 (RTA-RETICS), by the Spanish Ministry of Science and Technology, Consolider-C #SAF2007-64062 and #SAF2011-29864, the Catalan Government (SGR2009-00731), and by the Catalan Institution for Research and Advanced Studies (ICREA Academia program). Ainhoa Plaza-Zabala and África Flores are recipients of a predoctoral fellowship from the Spanish Ministry of Education

Frustration represents a particular aspect of the addictive process that is related to loss of control when the expected reward is not obtained. We aim to study the consequences of frustrated expected reward on gene expression in the mouse brain. For this purpose, we used an operant model of frustration using palatable food as reward combined with microarrays. Transcriptomic profiles of frontal cortex, ventral striatum and hippocampus were analysed in five groups of mice: (1) positive control receiving palatable food and the cue light as conditioned stimulus; (2) frustrated group only receiving the cue light; (3) extinction learning group that did not receive palatable food nor the light; (4) negative control that never received the reinforcer nor the light during the whole experiment; and (5) yoked that received palatable food passively. Gene expression changes produced by frustration were revealed in the frontal cortex and ventral striatum, but not in the hippocampus. Most of the changes, such as the modification of the dopamine-DARPP-32 signalling pathway, were common in both areas and estimated to have neuronal origin. Extinction learning induced transcriptional changes only in the ventral striatum, with most genes showing down-regulation and without alteration in the dopamine-DARPP-32 signalling pathway. Active palatable food-seeking behaviour induced changes in gene expression in ventral striatum mainly affecting cell communication. In conclusion, frustration behaviour-induced changes in frontal cortex and ventral striatum mainly related to dopamine-DARPP-32 signalling that could play an important role in the loss of behavioural control during the addictive processes. ; This work was supported by the Spanish 'Instituto de Salud Carlos III' (RTA,RD06/001/001andPI11/01629), the Spanish 'Ministerio de Ciencia e Innovación' (SAF2007-64062 and SAF2012-33484), the Spanish 'Ministerio de Sanidad y Política Social' (Plan Nacional Sobre Drogas, no. 2009/022 and 2009/026), the Catalan Government (2009-SGR-00131 and 2014-SGR-0932), the ICREA Foundation (ICREA Academia-2008). The research leading to these results has also received funding from the European Community's Seventh Framework Programme (FP7/2007–2013) under Grant Agreement No. 602805. A.B. was supported by a FI predoctoral fellowship of the Catalan Government, J.G-C. was supported by a 'Juan de la Cierva' post-doctoral fellowship from the Spanish 'Ministerio de Ciencia e Innovación', E.M-G. was supported by a 'Sara Borrell' post-doctoral fellowship from the Spanish 'Instituto de Salud Carlos III', N.F-C.was supported by a contract from the Biomedical Network Research Centre on Rare Diseases (CIBERER) and M.R. was supported by a 'Miguel i Servet' contract the Spanish 'Instituto de Salud Carlos III'. Partial support from FEDER funds is also acknowledged

Palatability enhances food intake by hedonic mechanisms that prevail over caloric necessities. Different studies have demonstrated the role of endogenous cannabinoids in the mesocorticolimbic system in controlling food hedonic value and consumption. We hypothesize that the endogenous cannabinoid system could also be involved in the development of food-induced behavioral alterations, such as food-seeking and binge-eating, by a mechanism that requires neuroplastic changes in the brain reward pathway. For this purpose, we evaluated the role of the CB1 cannabinoid receptor (CB1-R) in the behavioral and neuroplastic changes induced by operant training for standard, highly caloric or highly palatable isocaloric food using different genetics, viral and pharmacological approaches. Neuroplasticity was evaluated by measuring changes in dendritic spine density in neurons previously labeled with the dye DiI. Only operant training to obtain highly palatable isocaloric food induced neuroplastic changes in neurons of the nucleus accumbens shell and prefrontal cortex that were associated to changes in food-seeking behavior. These behavioral and neuroplastic modifications induced by highly palatable isocaloric food were dependent on the activity of the CB1-R. Neuroplastic changes induced by highly palatable isocaloric food are similar to those produced by some drugs of abuse and may be crucial in the alteration of food-seeking behavior leading to overweight and obesity. ; This work was supported by the Spanish Ministerio de Ciencia e Innovació (#SAF2007-64062 and #SAF2008-00962), the Instituto de Salud CarlosIII (#RD06/001/001), the Plan Nacional sobre Drogas, the Catalan Government (SGR2009-00131 and SGR2009-224), the ICREA Foundation (ICREA Academia-2008), the DG Research of the European Commission (GENADDICT,/n#LSHM-CT-2004-05166; and PHECOMP, #LSHM-CT-2007-037669) the FIS'' (PI07/0715),ATIP-Avenir and Sanofi-Aventis grants.This work was also supported by the Plan Nacional Sobre Drogas (#2009/026) to R.M.

Background: The chaperone ClpB, a bacterial protein, is a conformational antigen-mimetic of α-melanocyte-stimulating hormone (α-MSH) implicated in body weight regulation in mice. We here investigated the potential associations of gut bacterial ClpB-like gene function with obesity status and gut microbiota in humans. Results: Gut microbiota ClpB KEGG function was negatively associated with body mass index, waist circumference, and total fat mass (DEXA). The relative abundance (RA) of several phyla and families directly associated with ClpB was decreased in subjects with obesity. Specifically, the RA of Rikenellaceae, Clostridiaceae and not assigned Firmicutes were lower in subjects with obesity and positively associated with gut bacterial ClpB-like gene function (not assigned Firmicutes (r = 0.405, FDR = 2.93 × 10-2), Rikenellaceae (r = 0.217, FDR = 0.031), and Clostridiaceae (r = 0.239, FDR = 0.017)). The gut bacterial ClpB-like gene function was also linked to specific plasma metabolites (hippuric acid and 3-indolepropionic acid) and fecal lupeol. The α-MSH-like epitope similar to that of Escherichia coli ClpB was also identified in some sequences of those bacterial families. After fecal transplantation from humans to mice, the families that more contributed to ClpB-like gene function in humans were also associated with ClpB-like gene function in mice after adjusting for the donor's body mass index (not assigned Firmicutes (r = 0.621, p = 0.003), Prevotellaceae (r = 0.725, p = 4.1 × 10-7), Rikenellaceae (r = 0.702, p = 3.9 × 10-4), and Ruminococcaceae (r = 0.526, p = 0.014)). Clostridiaceae (r = - 0.445, p = 0.038) and Prevotellaceae RA (r = - 0.479, p = 0.024) and were also negatively associated with weight gain in mice. The absolute abundance (AA) of Prevotellaceae in mice was also positively associated with the gut bacterial ClpB-like gene function in mice. DESeq2 identified species of Prevotellaceae, both negatively associated with mice' weight gain and positively with gut bacterial ClpB-like gene function. Conclusions: In summary, gut bacterial ClpB-like gene function is associated with obesity status, a specific gut microbiota composition and a plasma metabolomics profile in humans that could be partially transplanted to mice. Video Abstract. ; This work was partially supported by research grants FIS (PI15/01934) from the Instituto de Salud Carlos III from Spain, SAF2015-65878-R from Ministry of Economy and Competitiveness, Prometeo/2018/A/133 from Generalitat Valenciana, Spain and also by Fondo Europeo de Desarrollo Regional (FEDER) funds, European Commission (FP7, NeuroPain #2013-602891), the Catalan Government (AGAUR, #SGR2017-669, ICREA Academia Award 2015), the Instituto de Salud Carlos III (RTA, #RD16/0017/0020), and the European Regional Development Fund (No. 01.2.2-LMT-K-718-02-0014). María Arnoriaga-Rodríguez is funded by Instituto de Salud Carlos III, Río Hortega (CP19/00190). Jordi Mayneris-Perxachs is funded by Instituto de Salud Carlos III, Miguel Servet (CP18/00009). The project has also been 65% cofinanced by the European Regional Development Fund (ERDF) through the Interreg V-A Spain-France-Andorra programme (POCTEFA 2014-2020). POCTEFA aims to reinforce the economic and social integration of the French–Spanish–Andorran border. Its support is focused on developing economic, social and environmental cross-border activities through joint strategies favouring sustainable territorial development.

Multiple studies in animal models and humans suggest that the endogenous opioid system is an important neurobiological substrate for nicotine addictive properties. In this study, we evaluated the participation of δ-opioid receptors in different behavioral responses of nicotine by using δ-opioid receptor knockout mice. Acute nicotine administration induced hypolocomotion and antinociception in wild-type mice, which were similar in knockout animals. The development of tolerance to nicotine-induced antinociception was also similar in both genotypes. In agreement, the expression and functional activity of δ-opioid receptors were not modified in the different layers of the spinal cord and brain areas evaluated after chronic nicotine treatment. The somatic manifestation of the nicotine withdrawal syndrome precipitated by mecamylamine was also similar in wild-type and δ-opioid receptor knockout mice. In contrast, nicotine induced a conditioned place preference in wild-type animals that was abolished in knockout mice. Moreover, a lower percentage of acquisition of intravenous nicotine self-administration was observed in mice lacking δ-opioid receptors as well as in wild-type mice treated with the selective δ-opioid receptor antagonist naltrindole. Accordingly, in-vivo microdialysis studies revealed that the enhancement in dopamine extracellular levels induced by nicotine in the nucleus accumbens was reduced in mutant mice. In summary, the present results show that δ-opioid receptors are involved in the modulation of nicotine rewarding effects. However, this opioid receptor does not participate either in several acute effects of nicotine or in the development of tolerance and physical dependence induced by chronic nicotine administration. ; This work was supported by the Spanish "Ministerio de Ciencia e Innovación"/n(#SAF2007-64062 and #SAF-2011-29864), the "Instituto de Salud Carlos III" grants/n#PI07/0559, #PI10/00316 and #RD06/001/001, the "Plan Nacional Sobre Drogas"/n(#2009/026), the Catalan Government (SGR2009-00131), and the ICREA Foundation/n(ICREA Academia Award-2008) to R.M. Partial support of FEDER funds is also acknowledged.

An increasing perspective conceptualizes obesity and overeating as disorders related to addictive-like processes that could share common neurobiological mechanisms. In the present study, we aimed at validating an animal model of eating addictive-like behavior in mice, based on the DSM-5 substance use disorder criteria, using operant conditioning maintained by highly palatable chocolate-flavored pellets. For this purpose, we evaluated persistence of food-seeking during a period of non-availability of food, motivation for food, and perseverance of responding when the reward was associated with a punishment. This model has allowed identifying extreme subpopulations of mice related to addictive-like behavior. We investigated in these subpopulations the epigenetic and proteomic changes. A significant decrease in DNA methylation of CNR1 gene promoter was revealed in the prefrontal cortex of addict-like mice, which was associated with an upregulation of CB1 protein expression in the same brain area. The pharmacological blockade (rimonabant 3 mg/kg; i.p.) of CB1 receptor during the late training period reduced the percentage of mice that accomplished addiction criteria, which is in agreement with the reduced performance of CB1 knockout mice in this operant training. Proteomic studies have identified proteins differentially expressed in mice vulnerable or not to addictive-like behavior in the hippocampus, striatum, and prefrontal cortex. These changes included proteins involved in impulsivity-like behavior, synaptic plasticity, and cannabinoid signaling modulation, such as alpha-synuclein, phosphatase 1-alpha, doublecortin-like kinase 2, and diacylglycerol kinase zeta, and were validated by immunoblotting. This model provides an excellent tool to investigate the neurobiological substrate underlying the vulnerability to develop eating addictive-like behavior. ; This work was supported by the DG Research of the European Commission FP7 (No. HEALTH-F2 2013-602891), the Spanish 'RETICS-Instituto de Salud Carlos III' (No. RD12/0028/0023), the Spanish 'Ministerio de Ciencia e Innovación' (No. SAF2011-29864), and the Catalan Government 'AGAUR-Generalitat de Catalunya' (Nos. 2009SGR00731 and 2014-SGR-1547). The FEDER funds support is also acknowledged. SM and AB were supported by FI predoctoral fellowships of the Catalan Government, and JG-C was supported by a 'Juan de la Cierva' postdoctoral fellowship from the Spanish 'Ministerio de Ciencia e Innovación'. Also support by the Italian Ministry of University and Research under grants FIRB-RBFR12DELS to CDA and PRIN2010-11 to MM is gratefully acknowledged. The authors declare no conflict of interest.

Background: Gonadal steroid hormones have been suggested as the underlying mechanism responsible for the sexual dimorphism observed in metabolic diseases. Animal studies have also evidenced a causal role of the gut microbiome and metabolic health. However, the role of sexual dimorphism in the gut microbiota and the potential role of the microbiome in influencing sex steroid hormones and shaping sexually dimorphic susceptibility to disease have been largely overlooked. Although there is some evidence of sex-specific differences in the gut microbiota diversity, composition, and functionality, the results are inconsistent. Importantly, most of these studies have not taken into account the gonadal steroid status. Therefore, we investigated the gut microbiome composition and functionality in relation to sex, menopausal status, and circulating sex steroids. Results: No significant differences were found in alpha diversity indices among pre- and post-menopausal women and men, but beta diversity differed among groups. The gut microbiota from post-menopausal women was more similar to men than to pre-menopausal women. Metagenome functional analyses revealed no significant differences between post-menopausal women and men. Gonadal steroids were specifically associated with these differences. Hence, the gut microbiota of pre-menopausal women was more enriched in genes from the steroid biosynthesis and degradation pathways, with the former having the strongest fold change among all associated pathways. Microbial steroid pathways also had significant associations with the plasma levels of testosterone and progesterone. In addition, a specific microbiome signature was able to predict the circulating testosterone levels at baseline and after 1-year follow-up. In addition, this microbiome signature could be transmitted from humans to antibiotic-induced microbiome-depleted male mice, being able to predict donor's testosterone levels 4 weeks later, implying that the microbiota profile of the recipient mouse was influenced by the donor's gender. Finally, obesity eliminated most of the differences observed among non-obese pre-menopausal women, post-menopausal women, and men in the gut microbiota composition (Bray-Curtis and weighted unifrac beta diversity), functionality, and the gonadal steroid status. Conclusions: The present findings evidence clear differences in the gut microbial composition and functionality between men and women, which is eliminated by both menopausal and obesity status. We also reveal a tight link between the gut microbiota composition and the circulating levels of gonadal steroids, particularly testosterone. Video Abstract. ; This work was partially supported by research grants FIS (PI15/01934) from the Instituto de Salud Carlos III from Spain, SAF2015-65878-R and AEI-SAF2017-84060-R from Ministry of Economy and Competitiveness, Prometeo/2018/A/133 from Generalitat Valenciana, Spain, and also by European Commission (FP7, NeuroPain #2013-602891; #H2020-SC1-2019-2-RTD-848099 (PAINFACT)), the Catalan Government (AGAUR, #SGR2017-669, ICREA Academia Award 2015), the Spanish Instituto de Salud Carlos III (RTA, #RD16/0017/0020), the Fondo Europeo de Desarrollo Regional (FEDER) through the Programa Interreg V-A España-Francia-Andorra (POCTEFA 2014-2020), and the European Regional Development Fund (project No. 01.2.2-LMT-K-718-02-0014) under grant agreement with the Research Council of Lithuania (LMTLT). María Arnoriaga Rodríguez is funded by a predoctoral Río Hortega contract (CM19/00190, co-funded by European Social Fund "Investing in your future") from the Instituto de Salud Carlos III, Spain. Jordi Mayneris-Perxachs is funded by the Miguel Servet Program from the Instituto de Salud Carlos III (ISCIII CP18/00009), co-funded by the European Social Fund "Investing in your future".

Nicotine exerts its psychopharmacological effects by activating the nicotinic acetylcholine receptor (nAChR), composed of alpha and/or beta subunits, giving rise to a diverse population of receptors with a distinct pharmacology. β4-containing (β4*) nAChRs are located almost exclusively in the habenulo-interpeduncular pathway. We examined the role of β4* nAChRs in the medial habenula (MHb) and the interpeduncular nucleus (IPN) in nicotine reinforcement using behavioral, electrophysiological, and molecular techniques in transgenic mice. Nicotine intravenous self-administration (IVSA) was lower in constitutive β4 knockout (KO) mice at all doses tested (7.5, 15, 30, and 60 μg/kg/infusion) compared with wild-type (WT) mice. In vivo microdialysis showed that β4KO mice have higher extracellular dopamine (DA) levels in the nucleus accumbens than in WT mice, and exhibit a differential sensitivity to nicotine-induced DA outflow. Furthermore, electrophysiological recordings in the ventral tegmental area (VTA) demonstrated that DA neurons of β4KO mice are more sensitive to lower doses of nicotine than that of WT mice. Re-expression of β4* nAChRs in IPN neurons fully restored nicotine IVSA, and attenuated the increased sensitivity of VTA DA neurons to nicotine. These findings suggest that β4* nAChRs in the IPN have a role in maintaining nicotine IVSA ; This work was supported by the Spanish Instituto de Salud Carlos III (RD06/001/001 and PI10/01708; PI14/00210), FEDER funds, Ministerio de Ciencia e Innovación (#SAF2014-59648-P), the Catalan Government AGAUR (#2014-SGR-1547), Plan Nacional Sobre Drogas, Ministerio de Sanidad, Asuntos Sociales e Igualdad-MSASI (#PNSD- 2013-0068), FP7 ERANET program (NICO-GENE), the ICREA Foundation (ICREA Academia-2008), and a postdoctoral fellowship from CONACyT to AHS. The work in Paris was supported by the Institut Pasteur, Centre National de la Recherche Scientifique CNRS UMR 3571 (UM) and CNRS UMR 8246 (PF), the INSERM U1130 (PF), the Pierre et Marie Curie University (UM119), the Agence Nationale pour la Recherche (ANR Neuroscience), and FP7 ERANET program (NICO-GENE), Grant agreement n009 BLANC 20092009BLANC 20 NeuroCypres" project), Fondation EDF, the Fondation des Treilles, and the Foundation for Medical Research FMR (Equipe FRMDEQ20130326488 to PF). The groups of UM and PF are members of the Bio-Psy Labex. As such this work was supported by French state funds managed by the ANR within the Investissements d'Avenir programme under reference ANR-11-IDEX-0004-02. The teams of UM and PF are part of the École des Neurosciences de Paris Ile-de-France Network. We would like to thank Martine Soudant, Stephanie Pons, and Dulce Real for technical support, and Inés Ibañes-Tallon and Jessica/nAbles for providing the Tg(Chrnb4-cre)OL57Gsat/+ transgenic mice

Elements of the endocannabinoid system are strongly expressed in the basal ganglia where they suffer profound rearrangements after dopamine depletion. Modulation of the levels of the endocannabinoid 2-arachidonoyl-glycerol by inhibiting monoacylglycerol lipase alters glial phenotypes and provides neuroprotection in a mouse model of Parkinson's disease. In this study, we assessed whether inhibiting fatty acid amide hydrolase could also provide beneficial effects on the time course of this disease. The fatty acid amide hydrolase inhibitor, URB597, was administered chronically to mice treated with 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine and probenecid (MPTPp) over 5weeks. URB597 (1mg/kg) prevented MPTPp induced motor impairment but it did not preserve the dopamine levels in the nigrostriatal pathway or regulate glial cell activation. The symptomatic relief of URB597 was confirmed in haloperidol-induced catalepsy assays, where its anti-cataleptic effects were both blocked by antagonists of the two cannabinoid receptors (CB1 and CB2), and abolished in animals deficient in these receptors. Other fatty acid amide hydrolase inhibitors, JNJ1661010 and TCF2, also had anti-cataleptic properties. Together, these results demonstrate an effect of fatty acid amide hydrolase inhibition on the motor symptoms of Parkinson's disease in two distinct experimental models that is mediated by cannabinoid receptors. ; This work was supported by the projects PI14/02070 and SAF2012-39875-C02-01 from the Spanish Government (Plan estatal I+D+I 2013–2016 and ISCIII-FEDER), Fundación Gangoiti and the UTE-project/Foundation for Applied Medical Research (FIMA). Estefanía Rojo is supported by a predoctoral fellowship from Colfuturo. Partial support was also provided by the Research and Education Program of the Advancing a Healthier Wisconsin Endowment at the Medical College of Wisconsin

Social stress in adulthood enhances cocaine self-administration, an effect that has been related with an increase in extracellular signal-regulated kinase and p38α mitogen-activated protein kinase phosphorylation. A detrimental effect of cocaine on blood-brain barrier (BBB) integrity has also been reported. This study evaluates the effects of repeated social defeat (RSD) during adolescence on the reinforcing and motivational effects of cocaine in adult mice and the changes induced by RSD on BBB permeability. Cocaine self-administration, conditioned place preference and quantitative analysis of claudin-5, laminin, collagen-IV and IgG immunoreactivity took place 3 weeks after RSD. Mice socially defeated during adolescence developed conditioned place preference and exhibited reinstated preference with a non-effective dose of cocaine (1 mg/kg). RSD mice needed significantly more sessions than control animals for the preference induced by 25 mg/kg of cocaine to be extinguished. However, acquisition of cocaine self-administration (0.5 mg/kg per injection) was delayed in the RSD group. Mice exposed to RSD displayed significant changes in BBB structure in adulthood, with a marked reduction in expression of the tight junction protein claudin-5 and an increase in basal laminin degradation (reflected by a decrease in laminin and collagen-IV expression) in the nucleus accumbens and hippocampus. The detrimental effect induced by cocaine (25 mg/kg) on collagen-IV expression in the hippocampus was more pronounced in RSD mice. In summary, our findings suggest that stress and cocaine can increase the long-term vulnerability of the brain to subsequent environmental insults as a consequence of a sustained disruption of the BBB. ; This work was supported by the Spanish Ministerio de Economía y Competitividad 'Instituto de Salud Carlos III', RETICS: RD12/0028/0005, RD12/0028/0023, RD12/0028/0002, PSI2011-24762, PSI2014-51847-R, SAF2011-29864 and SAF2013-40592-R. It is also supported by the Catalan Government (2014SGR1547) and the Valenciano Government (PROMETEOII/2014/063). The research leading to these results has also received funding from the European Community's Seventh Framework Programme (NEUROPAIN, HEALTH-F2-2013)