La queue de l'aire tegmentale ventrale (tVTA) est une région cérébrale GABAergique localisée en arrière de la VTA. Elle projette de façon massive aux neurones dopaminergiques des groupes A9 et A10 du mésencéphale à l'origine des systèmes nigrostrié et mésolimbique. Ces systèmes sont impliqués dans de nombreuses fonctions comme la motricité et les comportements associés aux drogues. L'objectif de ma thèse est d'étudier le rôle de la tVTA via ses projections sur ces systèmes. Pour cela, nous avons utilisé des approches variées comprenant l'immunohistochimie, la pharmacologie in vivo,l'électrophysiologie in vivo et l'étude du comportement moteur. Parmi un ensemble de drogues appartenant à différentes classes, l'activation moléculaire de la tVTA sous forme de l'induction de FosB/ΔFosB est spécifique des psychostimulants et dépend de la dopamine. D'un point de vue physiologique, la tVTA exerce un tonus inhibiteur sur les neurones dopaminergiques de la VTA et joue un rôle crucial dans leur désinhibition par la morphine. Enfin, des lésions de la tVTA influencent des comportements dépendant du système nigrostrié comme le comportement de rotation provoqué par l'amphétamine, les performances motrices et l'apprentissage moteur. / The tail of the ventral tegmenta area (tVTA) is a GABAergic brain region located behind the VTA. It projects massively to dopaminergic neurons in mesencephalic A9 and A10 groups leading to nigrostriatal and mesolimbic systems that play a role in fonctions like motricity and drug-related behaviours. The objective of my thesis is to study the tVTA role through its projections to these systems. For that, we used various approaches including immunohistochemistry, in vivo pharmacology, in vivo electrophysiology, and motor behaviour. Between various drugs belonging to different classes, molecular activation of the tVTA by FosB/ΔFosB induction is only observed following psychostimulant treatment and is mediated by dopamine. From a physiological point of view, the tVTA exerts an inhibitory tone onto VTA dopamine neurons and plays a crucial role in morphine-induced desinhibition. Finally, tVTA lesions modulate nigrostriatal system mediated behaviour like amphetamine-induced rotational behaviour, motor coordination and motor skill learning.

Estudos reportando que a autoadministração repetida de drogas de abuso causa mudanças comportamentais, e na expressão de FosB, diferentes às causadas pela administração passiva repetida da mesma droga, em conjunto com estudos de discriminação de estímulos, têm sido chaves para compreender a dependência às drogas. Neste estudo se apresentam resultados de 3 experimentos que avaliaram diferenças gênicas e comportamentais entre a autoadministração de morfina e cocaína sob uma contingência operante, e a administração passiva destas drogas sob uma contingência Pavloviana, usando um modelo de administração de drogas acoplado e um protocolo de transferência operante-Pavloviana (PIT) seletiva em ratos. Os sujeitos foram distribuídos em três grupos: Administração por Contingência Operante (CO), Administração por Contingência Pavloviana (CP) e Controle (Ctr). No Experimento 1, cada sujeito do grupo CO foi exposto a sessões de autoadministração endovenosa de morfina. Depois, a expressão do gene FosB foi medida utilizando uma técnica imuno-histoquímicas em diferentes áreas do cérebro. No Experimento 2 os ratos foram expostos a um protocolo de PIT, treinando de forma inicial as contingências operante e Pavloviana separadamente, em associação a S1, utilizando infusões de morfina como reforçador. Em seguida foi treinado um encadeado de respostas (busca e administração) e finalmente, os sujeitos foram testados para avaliar o controle de estímulos que S1 adquiriu sobre as respostas de busca e administração. O Experimento 3 foi realizado utilizando os métodos dos primeiros dois experimentos, utilizando cocaína como reforçador. Em conjunto, os dados imunohistoquímicos e comportamentais sugerem que a maior expressão de FosB em subáreas envolvidas na dependência às drogas, em comparação entre os grupos CO e CP, está relacionada ao controle de estímulos estabelecido por S1 pelas diferentes contingências de aprendizagem. Ainda, os resultados apontam que estas áreas em que se encontrou uma expressão de FosB diferencial por diferentes contingências de administração de drogas coincidem com algumas das reportadas como envolvidas na PIT. Os resultados estão em concordância com estudos que reportam que a administração repetida de uma droga em contingências operantes ou pavlovianas alteram diferencialmente estruturas cerebrais envolvidas nos processos da dependência às drogas e apoiam a literatura que reporta que o estabelecimento de controle de estímulos que caracteriza a dependência se pode estabelecer por processos de aprendizagem na contingência operante e Pavloviana / Studies reporting that repeated drug self-administration produces behavioral changes, and in FosB expression, different from those produced by repeated passive administration of the same drug have been very important, together with stimulus control studies, have been the key to understand mechanisms underlying drug abuse. This study presents results from 3 experiments evaluating gene and behavioral differences between self-administration of morphine and cocaine under an operant contingency, and passive administration of these drugs under a Pavlovian contingency, using a yoked drug administration model and a selective Pavlovian to instrumental transfer (PIT) protocol in rats. Subjects were divided into three groups: Operant Contingency Administration (CO), Pavlovian Contingency Administration (CP) and Control (Ctr). In Experiment 1, each subject in the CO group was exposed to intravenous morphine self-administration sessions. Then, expression of FosB gene was measured using an immunohistochemical technique in different areas of the brain. In Experiment 2 rats were exposed to a PIT protocol, initially training the operant and Pavlovian contingencies separately in association with S1, using morphine infusions as a reinforcer. Then a chain of responses (seeking and taking) was trained and finally, subjects were tested to evaluate S1 stimulus control over search and administration responses. Experiment 3 was performed using the methods from the first two experiments, using cocaine as a reinforcer. Together, immunohistochemical and behavioral data interact and suggest that a higher expression on FosB expression in subareas involved in drug dependence, in comparison between CO and CP groups, is related to stimuli control established by S1 through the different learning contingencies. Moreover, results point out these same areas in which different FosB expression was found by different drug administration contingencies match some of those reported as being involved in PIT. Results are in agreement with studies reporting that repeated administration of a drug in operant or pavlovian contingencies differentially alter brain structures involved in drug dependence processes and support literature reporting the establishment of stimulus control characterizing addiction can be establish by learning processes in the operant and Pavlovian contingencies

Une influence des conditions de vie sur le phénomène de dépendance a été observée chez l'Homme et modélisée chez l'animal. Ainsi chez les rongeurs, l'exposition à un environnement enrichi (EE) réduit le risque d'addiction, alors qu'un stress l'augmente. Les mécanismes responsables de ces influences environnementales sur la dépendance ont été l'objet de mes recherches. D'une part, nous avons montré que des injections chroniques de cocaïne augmentent l'expression du facteur de transcription ΔFosB dans les cellules striatales exprimant le récepteur dopaminergique D1R (D1R+), alors que l'EE seul l'augmente spécifiquement dans les cellules D1R(-). De façon intéressante, ces effets sont abolis lorsque la cocaïne est administrée à des souris exposées à l'EE. Ces résultats suggèrent que la prévention de la sensibilisation comportementale par l'EE corrèle avec une accumulation modifiée de ΔFosB. D'autre part, le laboratoire avait montré que le passage d'un EE à un environnement standard augmentait la vulnérabilité à la cocaïne. Toujours dans le but de découvrir les mécanismes impliqués, nous nous sommes intéressés au système endocannabinoïde (ECS), un régulateur du stress et aux processus épigénétiques. Nous avons observé que ce switch environnemental modulait l'expression de différents acteurs de l'ECS, en particulier le récepteur CB1 dans l'amygdale, et aussi celle de la protéine régulatrice de la transcription MeCP2 (Methyl CpG-binding-Protein-2) dans le noyau accumbens. Dans son ensemble, ce travail a permis d'identifier des mécanismes moléculaires, régulés par différentes manipulations environnementales, et pouvant participer à la vulnérabilité aux drogues d'abus. / Influences of life conditions on the phenomenon of addiction has been observed in Human and modeled in animals. Indeed, in rodents, exposure to enriched environment (EE) reduces the risk of addiction, whereas stress increases it. The mechanisms responsible for these environmental influences on addiction have been the object of my thesis. On one hand, we have shown that chronic injections of cocaine increase the expression of the transcription factor ΔFosB in striatal cells expressing the dopaminergic receptor D1 (D1R(+) cells) whereas EE by itself increases it specifically in D1R(-) cells. Interestingly, these effects were abolished when cocaine is administrated to mice exposed to EE. These results suggest that the prevention of the behavioral sensitization induced by EE correlates with a modified accumulation of ΔFosB. On the other hand, our laboratory has shown that switching mice from EE to a standard environment increases the vulnerability to cocaine. In order to uncover the mechanisms underlying this potentiation, we studied the endocannabinoid system, involved in stress regulation and in epigenetic processes. We have observed that the environmental switch modulates the expression of different actors of the endocannabinoid system, especially the CB1 receptor in the amygdala, and of MeCP2 (Methyl CpG-binding-Protein-2), a protein involved in the control of transcription in the nucleus accumbens. Altogether, this work allowed us to highlight molecular mechanisms that are regulated by environmental manipulations and that could participate to the individual vulnerability to drugs of abuse.

Epilepsy is a devastating disorder characterized by recurrent seizures. The pathophysiology of the disorder is not well understood. In this study the effects of early life, including pre- and post-natal, experiences on the seizure susceptibility of offspring was determined. Sprague-Dawley rats were air transported prior to breeding (In-House), on gestation day 9 (G9), or G16. The maternal behaviour was scored from P2-P13. On P14, seizure susceptibility of pups was assessed by randomly assigning the pups into Naïve (control), Saline, lipopolysaccharides (LPS; 200 ?g/kg), Kainic acid (KA; 1.75 mg/kg) or Febrile Convulsion (FC; LPS followed by KA) groups. No effect of prenatal transport was found on seizure susceptibility. Licking and grooming (LG) maternal behaviour was associated with higher FC seizure susceptibility of offspring. Male pups were more susceptible to FC seizure than female pups. These results emphasize the dam-dependent and sex-dependent effects of early life experiences on seizure susceptibility of offspring.

abstract: Patients with schizophrenia have deficits in sensorimotor gating, the ability to gate out irrelevant stimuli in order to attend to relevant stimuli. Prepulse inhibition (PPI) of the startle response is a reliable and valid model of sensorimotor gating across species. Repeated D2-like agonist treatment alleviates prior PPI deficits in rats, termed a PPI recovery, and is observable 28 days after treatment. The aim of the current project is to illuminate the underlying mechanism for this persistent change of behavior and determine the clinical relevance of repeated D2-like agonist treatment. Our results revealed a significant increase in Delta FosB, a transcription factor, in the nucleus accumbens (NAc) 10 days after repeated D2-like agonist treatment. Additionally, we investigated if Delta FosB was necessary for long-lasting PPI recovery and discovered a bilateral infusion of dominant-negative Delta JunD prevented PPI recovery after repeated D2-like agonist treatment. To further develop the underlying mechanism of PPI recovery, we observed that dominant negative mutant cyclic adenosine monophosphate (cAMP) response biding element protein (CREB) prevented repeated D2-like agonist-induced Delta FosB expression in the NAc. We then compared our previous behavioral and intracellular findings to the results of repeated aripiprazole, a novel D2-like partial agonist antipsychotic, to determine if repeated D2-like receptor agonist action is a clinically relevant pharmacological approach. As compared to previous PPI recovery and Delta FosB expression after repeated D2-like agonist treatment, we found similar PPI recovery and Delta FosB expression after repeated aripiprazole treatment in rats. We can conclude that repeated D2-like agonist treatment produces persistent PPI recovery through CREB phosphorylation and Delta FosB, which is necessary for PPI recovery. Furthermore, this pharmacological approach produces behavioral and intracellular changes similar to an effective novel antipsychotic. These findings suggest the underlying intracellular mechanism for sustained PPI recovery is clinically relevant and may be a potential target of therapeutic intervention to alleviate sensorimotor gating deficits, which are associated with cognitive symptoms of schizophrenia. / Dissertation/Thesis / Ph.D. Psychology 2013

No description available.

Orientadora: Profª Drª Marcela Bermúdez Echeverry / Dissertação (mestrado) - Universidade Federal do ABC, Programa de Pós-Graduação em Neurociência e Cognição, 2015. / Estudos tem mostrado que o fator de transcricao FosB/ delta FosB e regulado em resposta ao tratamento cronico com antipsicoticos. Porem, so a regulacao do fator FosB no estriado pode ter uma relevancia funcional nas alteracoes motoras pelos antipsicoticos tipicos e atipicos, uma vez que o gene e expressado na via direta e indireta do estriado. Assim, o objetivo do presente trabalho foi determinar se as alteracoes motoras induzidas pela administracao cronica de haloperidol, olanzapina ou clozapina regulam a expressao do FosB de maneira diferenciada no estriado motor e limbico. Metodos: Camundongos adultos machos C57Bl receberam injecao intraperitoneal agudo, subcronico ou cronico de Haloperidol, Olanzapina ou Clozapina. Tambem foram avaliados os efeitos extrapiramidais. Experimento 1: Administracao subcronica (5 dias) foi estudado com haloperidol 4 mg/Kg, olanzapina 15 mg/Kg ou Clozapina 20 mg/Kg para confirmar o efeito cataleptico. Experimento 2: As alteracoes motoras apos do tratamento cronico (77 dias) foram avaliadas com o teste de catalepsia, campo aberto, rota rod, pole test e vacuous chewing movement, com as mesmas doses do experimento 2. No ultimo experimento a expressao da proteina FosB foi avaliada. Resultados: Experimento 1: Com a administracao subcronica tipicos e atipicos induzem a catalepsia, sendo menor com os atipicos. Experimento 2: O tratamento cronico com os dois grupos de neurolepticos induzem alteracoes motoras. Foi observado aumenta da imobilizacao no teste de catalepsia e no campo aberto, sendo maior no grupo Haloperidol. Tambem foi observado alteracao no rota rod. Los grupos Haloperidol e Olanzapina tiveram aumento da expressao do FosB no estriado dorsal e ventral. Porem, o grupo Olanzapina no mostrou aumento na regiao Core do nucleo accumbens, resultado oposto observado com a Clozapina, onde mostrou aumento da expressao na regiao limbica do estriado, sem ser significativo na parte dorsal. Conclusoes: O padrao da expressao do FosB na regiao Core do nucleo accumbens, pode ser correlacionado com os sintomas parkinsonianos induzidos pelos antipsicoticos atipicos como a Clozapina. Assim, a regiao Core, poder ser inclusa na circuitaria dos nucleos basais para o estudo das alteracoes motoras induzidas pelos antipsicoticos. / Background: Studies have shown that the transcription factor FosB/ÄFosB is upregulated in response to chronic neuroleptic treatment. Moreover, regulation of only the factor FosB in striatum might have functional relevance to the motor side effects by either typical or atypical neuroleptics, once this gene is expressed in striatal direct and indirect pathways. Therefore, the goal of this study was determine whether the motor side effects after chronic administration of haloperidol, olanzapine or clozapine shown differential regulation FosB expression in motor and limbic caudate putamen. Methods: Adult male mice C57Bl received either acute, subchronic, or chronic intraperitoneally injections of haloperidol, olanzapine or clozapine, and extrapyramidal effects were evaluated.. Experiment 1: Subchronic administration (5 days) was studied with haloperidol 4 mg/Kg, Olanzapine 15 mg/Kg and clozapine 20 mg/Kg to confirm a steady cataleptic effect. Experiment 2: the motor side effects after chronic treatment (77 days) was evaluated through the catalepsy test, open field, Rota Rod, pole test and vacuous chewing movements, with same doses that experiment 2. Expression FosB protein in the last experiment was examined. Results: Experiment 1: with subchronic administration both typical and atypical neuroleptics induced cataleptic effect, even though the effect was lower with olanzapine and clozapine Experiment 2: chronic treatment showed motor side effects in both neuroleptics groups, evaluated with catalepsy test, open field, with an increased immobilization time in haloperidol group. Also, an alteration in Rota Rod test was observed with both neuroleptics groups, however, haloperidol group was unique showing increased time in pole test, with a little number of vacuous chewing movements but not significant. Haloperidol and olanzapine groups showed increased FosB protein expression in dorsal and ventral striatum. However, olanzapine group had not expression in the Core region in accumbens nucleus, opposite to clozapine group that showed an enlarged expression in this limbic/motor region, with scarcely expression in dorsal striatum. Conclusions: A unique pattern of regulation of FosB expression in core region, accumbens nucleus, may correlates with parkinsonism effect of the atypical neuroleptics, clozapine. Therefore, core region could be included in the basal ganglia circuit to study motor alterations by neuroleptics.

Activator Protein-1(AP-1) family plays a central role in the transcriptional regulation of many genes that are associated with cell proliferation, migration, metastasis, and survival. Transforming growth factor beta (TGF-β) is a multi-functional regulatory cytokine that regulates many aspects of cellular function, including cellular proliferation, migration, and survival. This study investigated the role of FOS proteins in TGF-β signaling in prostate cancer cell proliferation, migration, and invasion. DU145 and PC3 prostate cancer cells were exposed to TGF-β1 at varying time and dosage, RT-PCR, western blot and immunofluorescence analyses were used to determine TGF-β1 effect on FOS mRNA and protein expression levels as well as FosB sub-cellular localization. Transient silencing of FOS protein was used to determine their role in cell proliferation, migration and invasion. Our data showed that FOS mRNA and proteins were differentially expressed in human prostate epithelial (RWPE-1) and prostate cancer cell lines (LNCaP, DU145, and PC3). TGF-β1 induced the expression of FosB at both the mRNA and protein levels in DU145 and PC3 cells, whereas cFos and Fra1 were unaffected and Fra2 protein expression increased in PC3 cell only. Immunofluorescence analysis showed an increase in the accumulation of FosB protein in the nucleus of PC3 cells after treatment with exogenous TGF-β1. Selective knockdown of endogenous FosB by specific siRNA did not have any effect on cell proliferation in PC3 and DU145 cells. However, basal and TGF-β1-and EGF- induced cell migration was significantly reduced in DU145 and PC3 cells lacking endogenous FosB. TGF-β1- and EGF-induced cell invasion were also significantly decreased after FosB knockdown in PC3 cells. Transient silencing of Fra2 resulted in decrease in cell proliferation in PC3 cells whereas transient silencing of cFos resulted in an increase in cell number in PC3 cells. And lastly, TGF-β1 reduced FosB: cJun dimerization; cJun knockdown increased cell migration in PC3 cells and its over expression decreased cell migration in DU145 cells. Our data suggest that FosB is required for migration and invasion in prostate cancer cells. We also conclude that TGF-β1 effect on prostate cancer cell migration and invasion may be mediated through the induction of FosB.

Tesis por compendio / La exposición crónica a sustancias de abuso lleva a cambios adaptativos en el cerebro que implican alteraciones en la expresión génica. Se ha propuesto que los factores de transcripción CREB y deltaFosB serían dianas moleculares para la regulación de la plasticidad, la cual lleva a la adicción.En este trabajo hemos estudiado los cambios en la activación de CREB, en PVN y NTS, y las quinasas que mediarían su activación durante la dependencia y síndrome de abstinencia a morfina, así como la respuesta del eje HHA durante dicho síndrome. También se investigó la posibilidad de que la activación de CREB y su coactivador transcripcional TORC1 dependan de la activación de receptores adrenérgicos. Además se evaluaron las posibles modificaciones en la expresión de FosB/deltaFosB en diferentes áreas cerebrales implicadas en la adicción, así como los cambios neuroendocrinos/neuroquímicos responsables de las alteraciones metabólicas observadas durante el tratamiento crónico con morfina. / Chronic exposure to opioids and other abused drugs results in adaptive changes in the brain involving alterations in gene expression. It is proposed that the transcription factors CREB and deltaFosB be molecular targets for the regulation of plasticity, which leads to addiction.In this work we studied changes in activation of the cAMP-response element binding protein (CREB) in PVN and NTS and the kinases that may mediate this activation during dependence and morphine withdrawal and the HPA axis response after naloxone-induced morphine withdrawal. We also investigated the possibility that the activation of CREB and the transcriptional coactivator of CREB, TORC1, arises from the activation of adrenergic receptors. We also evaluated the possible modifications in FosB/deltaFosB expression in several brain areas involved in addiction and neuroendocrine/neurochemical changes that are responsible for the metabolic alterations seen during chronic morphine treatment.