Thesis (Ph.D. (Physiology))--Mahidol University, 1984.

Thesis (Ph. D.)--University of Washington, 2002. / Vita. Includes bibliographical references (leaves 138-142).

Diss. (sammanfattning) Göteborg : Univ., 2009. / Härtill 3 uppsatser.

Stroke is a leading cause of neurological disability, often resulting in long-term motor impairments due to damage to the striatum and/or motor cortex. While both humans and animals show spontaneous recovery following stroke, little is known about how the injury location affects recovery and what causes recovery to plateau. This information is essential in order to improve current rehabilitation practice and develop new therapies to enhance recovery. In this thesis, we used endothelin-1 (ET-1), a potent vasoconstrictor, to produce focal infarcts in the forelimb motor cortex (FMC), the dorsolateral striatum (DLS) or both the FMC and DLS in male Sprague-Dawley rats. In the first experiment, the spontaneous recovery profile of animals was followed over an 8-week period using multiple behavioural tasks assessing motor function and limb preference to identify how recovery varies depending on injury location. Infarct volumes were measured to determine the association between injury and behavioural outcome. All three groups had significant functional impairments on the Montoya staircase, beam traversal, and cylinder tests following stroke, with the combined group having the largest and most persistent impairments. Importantly, spontaneous recovery was not simply dependent on lesion volume but on the lesion location and the behavioural test employed. In the second experiment, we focused on a potential cellular mechanism thought to underlie post-stroke plasticity and functional recovery. In a separate cohort of animals, we assessed how plasticity-limiting perineuronal nets (PNNs) and associated parvalbumin-positive (PV) GABAergic interneurons change following similar ET-1 strokes as in the prior experiment. A significant reduction in the density of PNNs was observed in the perilesional cortex of animals that received a cortical-only or combined stroke but not a striatal-only injury. Although there were no significant differences in the density of PV interneurons between sham and stroked groups, a significant negative correlation existed between cortical infarct volume and the density of PV interneurons in the perilesional cortex. Taken together these results demonstrate that lesion location influences motor recovery and neuroplastic changes following stroke. This supports the idea that a “one size fits all” approach for stroke rehabilitation may not be effective and treatment needs to be individualized to the patient.

Orientador: Prof. Dr. Alexandre Hiroaki Kihara / Tese (doutorado) - Universidade Federal do ABC, Programa de Pós-Graduação em Neurociência e Cognição, 2017. / O estriado é a maior estrutura dos núcleos basais (NB), recebendo inputs sinápticos de várias regiões. Ele está envolvido no controle de várias funções, incluindo a motora, cognitiva e emocional, além de ser essencial para a organização e execução de ações voluntárias. Os canais de junções comunicantes (JC) são responsáveis por vários processos essenciais, incluindo a sincronização da atividade neuronal e a propagação da apoptose em doenças neurodegenerativas. Por outro lado, o papel da comunicação mediada por Cx no desenvolvimento do SNC permanece mal compreendido. Neste estudo investigamos a expressão gênica e os níveis proteicos da Cx36, Cx43 e Cx45 no estriado de ratos ao longo do desenvolvimento, na idade de E19 (embrionária) P5, P10 (pós-natais) e P60 (adulto), usando PCR em tempo real e wester blotting, respectivamente. Em seguida, examinamos os possíveis papéis dos canais de Cx36, principal Cx neuronal, no estriado em desenvolvimento. Para esta finalidade, realizamos injeções bilaterais in vivo de quinina, um bloqueador seletivo de Cx36, no estriado de ratos P0. Nossos resultados mostraram que Cx36, Cx43 e Cx45 possuem níveis de RNAm distintos durante o desenvolvimento do estriado. Nós observados que os níveis da expressão gênica da Cx36 e Cx45 foram mais altos durante o desenvolvimento quando comparados com P60 (P <0,05), enquanto Cx43 teve níveis mais baixos durante o desenvolvimento, nas idades de E19 e P5, em relação à P60 (P <0,05). O nível proteico da Cx36 em E19 foi maior quando comparado com todas as idades avaliadas e com o adulto (P <0,05). Por outro lado, nós observamos baixos níveis proteicos para Cx43 e Cx45 em todas as idades de desenvolvimento, comparado com P60 (P <0,05). Para analisar os dados de imuno-histoquímica, foram empregadas ferramentas matemáticas para avaliar em detalhe as alterações no padrão de distribuição das Cx36 e Cx45. Verificou-se que a distribuição dos diferentes tamanhos clusters/aglomerados decai semelhante a uma lei de potência, mas com diferentes valores exponenciais para P0 e P60, revelando tamanho de clusters maiores em P0 (P <0,05). Para Cx43, observou-se que esta proteína esteve distribuída uniformemente em toda a região do estriado, incluindo no interior das fibras que formam esta estrutura, padrão não observado para P60. Os resultados estatísticos mostraram uma diferença robusta comparando esses dois padrões de distribuição da proteína (P <0,0002). Nossos resultados da injeção in vivo demonstraram que os comportamentos motivados, como a alimentação, foram gravemente prejudicados nos filhotes. Além disto, a ontogênese de alguns reflexos motores foi adiada, como os comportamentos de aversão ao precipício e de geotaxia negativa. Finalmente, investigamos as conseqüências funcionais do bloqueio de Cx36 realizado no desenvolvimento pós-natal, avaliando o comportamento do rato adulto. Nossos experimentos mostraram que tanto o condicionamento do medo ao som quanto a coordenação motora foram afetados, revelando padrões distintos dos animais controle. Em conclusão a primeira parte do estudo, fomos capazes de revelar padrões de expressão distintos de Cxs em desenvolvimento do estriado, que provavelmente estão relacionados com processos fundamentais durante o desenvolvimento. Pudemos, também, determinar que a comunicação feita pelos canais Cx36 desempenham papéis essenciais no desenvolvimento do SNC, como revelado por nossas observações no estriado. / The striatum is the largest structure of the basal ganglia (BG), receiving synaptic input from multiple regions. It is involved in the control of various aspects of motor, cognitive, and emotional functions, besides being essential for the organization and execution of voluntary actions. Gap junction (GJ) channels are responsible for several essential processes, including synchronization of neuronal activity and spreading of apoptosis in neurodegenerative diseases. On the other hand, the role of Cx-mediated communication in the development of the CNS remains poorly understood. In this study we investigated gene expression and protein levels of Cx36, Cx43 and Cx45 in the striatum of rats along its developmental ages of E19 (embrionary), P5, P10 (postnatal day) and P60 (adult) using real time PCR and western blotting, respectively. We next examined the possible roles of Cx36 channels, the main neuronal Cx, in the developing striatum. To this end, we performed in vivo bilateral injections of quinine, a selective Cx36 blocker, in the striatum of P0 rats. Our results showed that Cx36, Cx43 and Cx45 have distinct mRNA expression during the development of striatum. We observed that Cx36 and Cx45 gene expression levels were higher during the development when compared to P60 (P<0.05), while Cx43 was lower in developmental ages of E19 and P5 (P<0.05) comparing to P60. Cx36 protein levels at E19 were higher when compared with all evaluated ages and to P60 (P<0.05). On the other hand, we observed lower protein levels of Cx43 and Cx45 along all development ages compared to P60 (P<0.05). For immunofluorescence, we employed mathematical analyses to evaluate in detail changes in Cx36 and Cx45 distribution of clusters size evaluation. It was found that the distribution of the clusters size decays similarly with a power law, but with different exponent values for P0 and P60, revealing larger mean clusters at P0 (P<0.05). For Cx43, we observed that this protein was uniformly distributed in the whole striatum, including inside the fibers that forms this structure, pattern not seen for P60. Statistical results showed a robust difference comparing those two patterns of protein distribution (P<0.0002). Our results from in vivo injection showed that motivated behaviors, such as feeding, were severely impaired in rat pups. Moreover, ontogenesis of some motor reflexes was delayed, as supported by cliff avoidance and negative geotaxis behavior tests. Finally, we focused on the functional consequences of Cx36 blockade performed in postnatal development by evaluating adult behavior. Our experiments showed that both tone fear conditioning and motor coordination were affected, revealing distinct from control animals. In conclusion from first part of this study, we were able to disclose distinct expression patterns of Cxs in developing striatum, which are probably related to fundamental processes during the development. We were, also, able to determine that communication provided by Cx36 channels play essential roles in the developing of the CNS, as revealed by our observations in the striatum.

abstract: ABSTRACT Auditory hallucinations are a characteristic symptom of schizophrenia. Research has documented that the auditory cortex is metabolically activated when this process occurs, and that imbalances in the dopaminergic transmission in the striatum contribute to its physiopathology. Most animal models have focused the effort on pharmacological approaches like non-competitive N-methyl-D-aspartate (NMDA) receptor antagonists to produce activation of the auditory cortex, or dopamine antagonists to alleviate it. I hypothesize that these perceptual phenomena can be explained by an imbalance activation of spiny projecting neurons in the striatal pathways, whereby supersensitive postsynaptic D2-like receptor, signaling in the posterior caudatoputamen generates activation of the auditory cortex. Therefore, I characterized the neuroanatomical component involved in the activation of the auditory cortex. I evaluated the participation of dopamine D2-like receptor using selective dopamine antagonist manipulations and identified the circuits related to the auditory cortex by retrograde trans-synaptic tracing using pseudorabies virus (PRV-152). My results show that dopamine infused in the posterior caudatoputamen dose dependently increases the transcription of the immediate early gene, zif268 in the auditory cortex, predominantly in layers III and IV, but also in cortical columns, suggesting enhanced functional auditory activity. This indicates the participation of the posterior striatum in the modulation of the secondary auditory cortex. I was able to demonstrate also that a coinfusion of a selective dopamine D2-like receptor antagonist, eticlopride and dopamine, attenuate the activation of the auditory cortex. Furthermore, using PRV-152 I delineate the distinctive circuit by axial mapping of the infected neurons. Thus, I found secondary projections from the posterior caudatoputamen that synapse in the thalamus before reaching the auditory cortex. These striatal projections correspond to the same brain region affected by dopamine during auditory cortical activation. My results further characterized a mechanism to generate intrinsic perception of sound that may be responsible for auditory hallucinations. I propose this paradigm may elucidate insight on the biological basis of psychotic behavior. / Dissertation/Thesis / Figure 9C. 3D brain reconstruction after 48 hours of PRV-152 inoculations / Figure 9A. 3D brain reconstruction after 24 h postinoculation / Figure 9B. 3D brain reconstruction after 36 h postinoculation / Doctoral Dissertation Neuroscience 2014

O óxido nítrico (NO) é uma molécula gasosa descrita recentemente, com implicações sobre uma vasta quantidade de processos fisiológicos, incluindo transmissão de sinais no sistema nervoso central (SNC). A sinalização nervosa mediada pelo NO ocorre por meios extrassinápticos, na chamada neurotransmissão por volume. Há evidências de que o NO seja um importante fator de modulação no controle da motricidade. A presença de neurônios que produzem NO já foi descrita em várias espécies, e estruturas ligadas ao controle do movimento como os núcleos da base (NNBB) contêm células nitrérgicas em quantidades variadas. Não se conhece os efeitos do processo de envelhecimento sobre a estrutura e função destes neurônios produtores de NO. O objetivo geral deste estudo foi investigar se o envelhecimento provoca alterações nos neurônios nitrérgicos presentes nos NNBB do encéfalo humano. Além disso, busca agregar mais conhecimento a aspectos morfológicos e de distribuição das células que compõem o sistema nitrérgico nos NNBB em humanos. As amostras de estriado (caudado e putâmen), globos pálidos (GP), núcleo subtalâmico (NST), substância negra (SN) e núcleo pedunculopontino (NPP) de 20 indivíduos sem doenças neurológicas e psiquiátricas foram submetidas à avaliação histológica em secções, coradas por técnicas que localizam neurônios que expressam NO, como a histoquímica para NADPH-diaforase (NADPHd) e à imunohistoquímica para sintase do NO neuronal (nNOS), e parâmetros de densidade neuronal e morfometria foram comparados entre indivíduos adultos jovens e idosos. Análises de densidade neuronal e morfometria entre subdivisões topográficas e funcionais também foram realizadas. Foi visto que o envelhecimento não provoca modificações na densidade neuronal e morfometria nitrérgica nos NNBB em humanos. Adicionalmente, o trabalho mostrou que: (I) as regiões mais posteriores do estriado se destacaram por apresentarem uma elevada densidade neuronal, associada a neurônios menores, em comparação com as regiões mais anteriores; (II) as porções do estriado ligadas ao córtex límbico apresentam maiores densidades neuronais; (III) o NST é uma região em que cerca de 90% de seus neurônios expressam NO, e suas características morfológicas sugerem que estas células coexpressem glutamato; (IV) o NPP é extensamente povoado por neurônios nitrérgicos, principalmente no nível do colículo inferior; (V) a presença de células NO-positivas é preponderante nas lâminas medulares de ambos GP, porém notamos maior concentração de células nitrérgicas no GPi; (VI) não foi detectada presença de neurônios quem contém NO na SN. Nossos resultados mostram que há uma presença maciça de neurônios que expressam NO em núcleos-chaves envolvidos com processamento motor corticobasal, como o NST, o estriado e o NPP, sugerindo que a neurotransmissão nitrérgica seja peça fundamental da fisiologia dos NNBB, portanto, com considerável potencial terapêutico nas doenças que afetam estas estruturas. / The nitric oxide (NO) is a gaseous molecule recently described, with a role on several physiologic processes, including signal transmission in central nervous system (CNS). The NO-mediated brain signaling occurs by extrasynaptic mode, called volume transmission. There are evidences supporting the NO as a major neurotransmitter involved on motor control modulation. The presence of NO neurons was described in many species, and movement-related structures, as the basal nuclei (BN), also contains variable densities of nitrergic cells. It is unknown the effect of aging over the structure and function of these NO neurons. The objective of the study is to investigate if the aging causes abnormalities on human BN nitrergic neurons. Furthermore, we aimed to explore distribution and morphologic features of these cells in BN. The samples of striatum (caudate and putamen), globus pallidum (GP), subthalamic nucleus (STN), substantia nigra (SN) and pedunculopontine nucleus (PPN) of 20 human brains from subjects without neurologic or psychiatric disases were processed for histologic analysis, stained by 2 techniques which localizes NO neurons: histochemistry for NADPH-diaphorase (NADPHd) and immunohistochemistry for neuronal NO synthase (nNOS); the neuronal density and morphometric parameters were compared between young adults and aged subjects. The neuronal density and morphometric analysis between striatal and subthalamic topographic / functional subdivisions were also performed. Our data showed that aging does not change the neuronal density or morphometric parameters of nitrergic neurons in human BN. Additionally, other results were found: (I) the most posterior regions of striatum have a higher neuronal density and smaller neurons than the most anterior regions of this nucleus; (II) the limbic cortex-associated areas of striatum have higher neuronal density than others functional subdivisions; (III) the STN is a region in which about 90% of its neurons expresses NO, and its morphologic features suggest these neurons coexpress glutamate; (IV) the PPN has a massive nitrergic neuronal density, mostly in the inferior colliculus level; (V) in GP, there is a marked presence of NO neurons in laminae medullaris, and the internal GP has more NO-positive cells than the external GP; (VI) nitrergic neurons were not detected in SN. Our results showed a remarkable presence of neurons expressing NO in nuclei essential for motor corticobasal processing (striatum, STN, PPN), suggesting that the nitrergic neurotransmission has a fundamental role in BN physiology, therefore, with great therapeutic potential in diseases involving these structures.

Orientadores: Fabio Rogério, Carlos Amilcar Parada / Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Biologia / Made available in DSpace on 2018-08-18T17:39:33Z (GMT). No. of bitstreams: 1 Ignarro_RaffaelaSilvestre_M.pdf: 3644274 bytes, checksum: 6e13f812b2d525e18878656d3ec27815 (MD5) Previous issue date: 2011 / Resumo: A injeção de ácido quinolínico (AQ), um agonista glutamatérgico do receptor N-metil-D-aspartato, no estriado de roedores induz morte seletiva de neurônios espinhosos médios, gliose reativa e neurogênese na zona subventricular, acompanhada da migração dos neurônios recém-gerados para o estriado lesado. Tais achados são também descritos na doença de Huntington (DH). Há indícios de que a via de sinalização JAK/STAT esteja envolvida no mecanismo de ação do AQ, bem como na patogênese da DH. A interação das citocinas da família da IL-6 com seus receptores desencadeia a ativação de enzimas da família das Janus-Quinases (JAKs), que por sua vez permitem o recrutamento e a ativação de fatores de transcrição da família das proteínas transdutoras de sinais e ativadoras da transcrição (STATs). Embora as principais características da DH sejam a presença da coréia e déficits na execução de movimentos voluntários, poucos testes são realizados abordando o comportamento locomotor dos animais no modelo de lesão por AQ. Neste trabalho, estudamos o efeito do AG490, um inibidor da JAK2, na gliose, perda neuronal e neurogênese no estriado de camundongos adultos C57BL/6J após a administração estereotáxica unilateral de AQ (30nmol). Imediatamente após a lesão, os animais receberam uma injeção subcutânea de AG490 (10mg/kg) ou veículo (PBS+DMSO), e injeções diárias por 6 dias adicionais. Além disso, investigamos o possível efeito da lesão por AQ na atividade física voluntária diária (AFVD) em rodas de atividade. A distância percorrida pelos camundongos foi monitorada por 28 dias após a injeção unilateral de QA (30nmol) ou PBS no estriado. Cortes coronais do cérebro (40?m) obtidos em criostato foram utilizados para quantificação de neurônios por estereologia e para a análise de expressão protéica, através de imunoistoquímica e Western Blotting para GFAP e doublecortina, marcadores de gliose e neuroblastos, respectivamente. A área total de células doublecortina-positivas (ACDP) e o número de neurônios (NN) no lado lesado (L) e contralateral à lesão (CL) foram avaliados. O Índice de Neurogênese (IN=ACDP(L)/ACDP(CL)) e o Índice de Sobrevivência Neuronal (ISN=NN(L)/NN(CL)) foram calculados. Após a administração de AQ, o estriado ipsilateral apresentou intensa gliose e células doublecortina positivas com características de células migratórias. O Western Blotting para GFAP mostrou uma redução ipsilateral de 19% nos animais tratados com AG490, em comparação aos animais do grupo tratado apenas com veículo (0.82±0.05; 1.010±0.06, n=9, p<0.05). O ISN foi 25% maior nos camundongos que receberam AG490 em comparação aos animais controles (0.75 ± 0.07; 0.60 ± 0.03; n=8, p<0.05). O IN mostrou uma diminuição de 21% no grupo AG490 em relação ao grupo de animais tratados apenas veículo de diluição (1.08±0.06; 1.37±0.09, n=5, p<0.05). A AFVD média, medida em quilômetros por dia, não se alterou nos animais que receberam injeção intra-estriatal de QA (30nmol) em comparação aos animais do grupo controle (3.97±0.34; 3.90±0.21, n=8, p>0.05). Portanto, nossos resultados suportam um papel para a JAK2 na morte neuronal, gliose, e neurogênese estriatais após lesão com AQ. O tratamento com o inibidor AG490 causou neuroproteção e diminuição da gliose, sugerindo que a reação astrocitária pode prejudicar a sobrevivência neuronal neste modelo experimental / Abstract: Injection of quinolinic acid (QA), a N-methyl-D-aspartate receptor agonist, in murine striatum induces death of medium spiny neurons, gliosis and neurogenesis in the subventricular zone with migration of newly synthesized neurons to damaged striatum. Such findings are also described in Huntington's disease (HD). The Janus-kinase (JAK) pathway would take part in QA mechanism of action and HD pathogenesis as well. The interaction of interleukin-6 family of cytokines with its receptor triggers the activation of enzymes of the family of JAKs, which in turn allow the recruitment and activation of transcription factors, known as signal transducers and activators of transcription (STATs). Although the main features of HD are the presence of chorea and deficits in performing voluntary movements, few tests are realized regarding locomotor behavioral on QA model. We studied the effect of AG490, an inhibitor of JAK isoform 2 (JAK2), on gliosis, neuronal loss and neurogenesis in the striatum of adult C57BL/6J mice after unilateral estereotaxic administration of QA (30 nmol). Immediately after injury, animals received a subcutaneous injection of AG490 (10 mg/kg) or vehicle (PBS + DMSO), and then once daily injections for 6 days. Furthermore, in a parallel experiment, we investigated the possible effect of the lesion by AQ on the voluntary daily physical activity (VDPA) in running wheels. The distance traveled by mice was monitored daily for 28 days after unilateral injection of QA (30 nmol) or PBS into the striatum. Frozen brain sections (40?m) were used for neuronal stereological quantification and immunohistochemical and Western Blotting analyses for GFAP and doublecortin, markers of gliosis and neuroblasts, respectively. The total area of doublecortin-positive cells (ADPC) and the number of neurons (NN) in the lesioned (L) and contralateral (CL) sides were evaluated. Neurogenesis index (NI = ADPC in L/ ADPC in CL) and neuronal survival ratio (NSR = NN in L/ NN in CL) were calculated. After QA administration, ipsilateral striatum showed intense gliosis and doublecortin-positive cells with few processes and ovoid bodies, morphological features corroborating a migratory activity. Western Blotting for GFAP showed an ipsilateral decrease of 19% in AG490- vs vehicle-treated animals (0.82 ± 0.05 vs 1.010 ± 0.06; n=9, p<0.05). NSR was 25% higher in mice given AG490 vs controls given vehicle (0.75 ± 0.07 vs 0.60 ± 0.03; n=8, p<0.05). NI showed a decrease of 21% in AG490- vs vehicle-treated mice (1.08 ± 0.06, 1.37 ± 0.09; n=5, p<0.05). The average VDPA, measured in kilometers per day for 28 days, has not changed in animals that received intrastriatal injection of QA (30nmol) compared to animals that received PBS (3.97 ± 0.34, 3.90 ± 0.21, n = 8, p> 0.05). In conclusion, our results support a role for JAK2 in striatal neuronal death, gliosis and neurogenesis determined by QA. AG490 caused neuroprotection and reduced gliosis suggesting that astrocytic reaction may impair neuronal survival in the present experimental model / Mestrado / Fisiologia / Mestre em Biologia Funcional e Molecular

Due to abnormal functioning of the brain’s reward and prediction system patients with schizophrenia spectrum disorders are thought to assign salience to non-relevant objects and events and to form context-inappropriate associations. The brain’s ventral striatum is critical in the formation of associations, and aberrant associations are believed to create delusional content during psychosis. The study wanted to examine the neural response, particularly in the ventral striatum, combined with subjective reports as patients learn associations in an aversive Pavlovian conditioning paradigm. The stimuli were randomized and involved circles of different colors. The conditioned stimuli (CS+) was followed by an unconditioned stimuli (US), consisting of an unpleasant sound, in 50% of events. The unconditioned (CS-) stimuli was followed by a low, not unpleasant sound in 50% of events. The degree of striatal activation was thought to be associated with the severity of patient’s illness. Functional magnetic resonance imaging (fMRI) blood-oxygen-level dependent (BOLD) responses were examined in eleven unmedicated non-institutionalized patients with schizophrenia spectrum disorders and 15 matched healthy controls. No significant within group differences in neural or subjective response to the [CS+ &gt; CS-] contrast were found. No significant associations between severity of illness and degree of striatal activation in response to CS+ or CS- were found. Significant differences in neural activation for the [CS+ &gt; CS-] contrast were found in the ventral striatum, the right inferor frontal gyrus, and the right angular gyrus, with patients exhibiting stronger activation compared to controls. The results and implications are discussed along with suggestions for future research.

Le striatum est composé principalement de neurones épineux de taille moyenne, subdivisés en neurones striatopallidaux et striatonigraux en fonction de leurs projections et de leur expression en récepteurs et neuropeptides. Ces deux populations neuronales sont respectivement à l’origine des voies indirecte (ou inhibitrice) et directe (ou activatrice) des noyaux de la base, présentant des effets opposés à la fois au niveau moteur et motivationnel. Ces deux voies sont également différemment affectées dans différentes pathologies des noyaux de la base, telles que les maladies de Huntington et de Parkinson et les addictions. Les mécanismes moléculaires et cellulaires de régulation des neurones STP et STN ne sont cependant pas encore pleinement compris. Dès lors, l’identification et l’étude de la fonction de gènes spécifiques de l’une ou l’autre de ces sous-populations pourraient constituer une étape importante vers une meilleure compréhension de leur fonctionnement. Dans cette optique, notre laboratoire a précédemment réalisé une étude comparative des profils d’expression de chacune des sous-populations striatales par microarray. Parmi les gènes potentiellement inégalement exprimés dans les neurones STP et STN, nous avons identifié GPRIN3, un membre de la famille G Protein-Regulated Inducer of Neurite outgrowth (GPRIN), comme étant une cible intéressante. Cette famille, bien qu’encore très peu caractérisée, interagit en effet avec les sous-unités Gαi/o des protéines G et joue par conséquent un rôle régulateur sur la fonction et la voie de signalisation de certains GPCRs, tels que le récepteur μ opioïde. De plus, contrairement aux autres membres de la famille GPRIN, nos résultats de microarray suggèrent également un niveau d’expression élevé de GPRIN3 dans les neurones striataux chez l’adulte. Etant donné le rôle crucial des GPCRs au niveau du striatum et plus particulièrement dans le comportement différentiel des neurones STP et STN, GPRIN3 pourrait dès lors constituer un élément important dans le fonctionnement des neurones striataux. Ce travail s'est par conséquent axé sur l’élucidation du rôle de GPRIN3 dans les fonctions striatales. Dans ce but, nous avons dans un premier temps établi le profil d'expression de GPRIN3 chez la souris, au niveau du cerveau adulte et lors de l'embryogénèse. Ceci nous a permis de confirmer, chez l'adulte, l'expression majoritairement striatale de GPRIN3, et l'expression préférentielle dans les neurones STP. Nous avons également généré différents vecteurs d'expression de la protéine GPRIN3 et établi sa localisation subcellulaire en lignée HEK293T. La génération et la caractérisation d'un modèle d'invalidation constitutive ainsi que d'un modèle de répression par interférence ARN ont par la suite mis en évidence une implication, directe ou indirecte, de GPRIN3 dans la régulation fine de la signalisation du D2R. En effet, nous avons montré une modification des comportements liés à la motivation et à la réponse à la cocaïne ainsi qu’une altération de l’état de phosphorylation de DARPP32 et de la réponse à l’halopéridol dans le modèle d’invalidation constitutive. De plus, la réponse au quinpirole est également modifiée dans les deux modèles testés. Pris dans leur ensemble, ces résultats suggèrent dès lors une altération de la voie de signalisation du D2R en l’absence de GPRIN3 fonctionnel. En outre, les neurones STP dépourvus de GPRIN3 fonctionnel présentent des modifications de leur morphologie et de leurs propriétés électrophysiologiques. En conclusion, ce travail de thèse a permis d’apporter les premières pistes quant à la fonction de GPRIN3, une protéine totalement méconnue, dans le striatum, de par la création de modèles d’invalidation constitutive et de répression Cre-dépendante de cette protéine. Divers outils moléculaires ont également été générés et pourront être utilisés dans la suite de la caractérisation des fonctions de GPRIN3. / Doctorat en Sciences biomédicales et pharmaceutiques (Médecine) / info:eu-repo/semantics/nonPublished