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Approche expérimentale de la physiopathologie des dyskinésies L-Dopa induites dans la maladie de Parkinson : comparaison de la cible classique, le striatum avec l’ensemble du cerveau / Multifunctional approach of L-Dopa induced dyskinesia pathophysiology in Parkinson’s disease : from the striatum to the whole brainBastide, Matthieu 18 September 2014 (has links)
Le traitement de référence de la maladie de Parkinson (MP) reste l’utilisation du précurseurdirect de la dopamine: la L-3,4-dihydroxyphenylalanine (L-Dopa). Le traitement chroniquedes patients parkinsoniens à la L-Dopa induit, en revanche, systématiquement desmouvements involontaires anormaux que l’on qualifie de dyskinésies induites par la L-Dopa(DIL). L’étude de l’expression des dyskinésies s’est essentiellement focalisée sur lesdysfonctions neuronales engendrées dans les régions motrices des ganglions de la base et apermis de révéler une surexpression significative de gènes de réponse précoce (GRP) tels que: ΔFosB, ARC, Zif268 et FRA2 dans le striatum de rats dyskinétiques traités chroniquement à la L–Dopa. En revanche, plusieurs autres régions dopaminoceptives, probablement affectées par la dopamine exogène nouvellement synthétisée, ont été négligées alors qu’elles pourraient jouer un rôle clé dans l’expression des dyskinésies. Par conséquent, nous avons quantifié l’expression de ΔFosB, ARC, FRA2 et Zif268 dans l’ensemble du cerveau de rats dyskinétiques que nous avons comparée à des rats non-dyskinétiques. Cette approche nous a permis d’identifier 9 structures, localisées en dehors des ganglions de la base, présentant une surexpression d’au moins 3 des GRPs cités ci-dessus. Parmi ces structures, le domaine dorsolatéral du « bed nucleus of the stria terminalis » (dlBST) et l’habenula latérale (LHb) montrent une corrélation significative entre l’expression de ΔFosB et la sévérité des dyskinésies. Nous avons donc fait l’hypothèse que ces 2 structures pouvaient être impliquées dans l’expression des dyskinésies. Par conséquent, pour évaluer le rôle potentiel du dlBST et de la LHb dans les dyskinésies, nous avons inhibé l’activité électrique des neurones exprimant FosB/ΔFosB en utilisant la méthode d’inactivation sélective du Daun02/ß-galactosidase que nous avons précédemment validée dans une structure bien connue pour être impliquée dans les dyskinésies: le striatum. Nous avons démontré que l’inhibition de ces neurones, à la fois dans le dlBST et la LHb, diminuait la sévérité des dyskinésies sans affecter l’effet bénéfique de la L-Dopa chez les rats dyskinétiques. Nous avons ensuite pu confirmer l’implication du dlBST grâce au model de référence des dyskinésies: le macaque dyskinétique lésé au MPTP. L’ensemble de ces résultats nous a ainsi permis de montrer, pour la première fois, l’implication fonctionnelle de 2 structures externes aux ganglions de la base dans l’expression des dyskinésies, offrant de nouvelles perspectives thérapeutiques. / The gold standard treatment for Parkinson’s disease (PD) remains the dopamine precursor L- 3,4-dihydroxyphenylalanine (L-Dopa). Long-term L-Dopa treatment systematically leads to abnormal involuntary movements (AIMs) called L-Dopa-induced dyskinesia (LID). These manifestations first led to investigate the neuronal dysfunctions in the motor regions of thebasal ganglia and unravelled an overexpression of ΔFosB, ARC, Zif268 and FRA2 immediate-early genes (IEG) in the dopamine-depleted striatum of dyskinetic rats. However, other several dopaminoceptive structures, likely affected by the exogenously produced dopamine, have been neglected although they might play a key role in mediating LID. Hence, we assessed the expression of ΔFosB, ARC, FRA2 and Zif268 IEGs in the whole brain of dyskinetic rats compared to non-dyskinetic ones. Such approach shed light notably upon 9 structures located outside of the basal ganglia displaying an IEG overexpression. Among them, the dorsolateral bed nucleus of the stria terminalis (dlBST) and the lateralhabenula (LHb) displayed a significant correlation between ΔFosB expression and LID severity. We therefore postulated that these structures might play a role in LID manifestation. Therefore, to assess dlBST and LHb causal roles upon LID severity, we inhibited the electrical activity of FosB/ΔFosB-expressing neurons using the selective Daun02/β- galactosidase inactivation method that we previously validated in a well known structure involve in LID: the striatum. Interestingly, the inactivation of dlBST and LHb ΔfosBexpressing neurons alleviated LID severity and increased the beneficial effect of L-Dopa in dyskinetic rats. Remarkably, BST involvement in LID was confirmed in the gold standard model of LID, the dyskinetic MPTP-lesioned macaque. Altogether, our results highlight for the first time the functional involvement of 2 structures.
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ÉTUDE NEUROCHIMIQUE ET COMPORTEMENTALE DES MODULATIONS INDUITES PAR LES RÉCEPTEURS OPIOÏDES DE TYPE δ SUR LES LIBÉRATIONS STRIATALES DE GLUTAMATE ET DE DOPAMINE CHEZ LE RATBillet, Fabrice 10 December 2007 (has links) (PDF)
Les enképhalines, ligands endogènes des récepteurs opioïdes δ, sont les neuropeptides les plus abondants du striatum, structure où elles stimulent la libération de dopamine. L'influence des récepteurs δ sur la transmission glutamatergique striatale, principalement supportée par les neurones corticaux, est en revanche méconnue. Néanmoins, des données suggèrent son implication dans la libération de dopamine induite par la DPDPE, agoniste sélectif des récepteurs δ. Nous avons exploré cette hypothèse chez le Rat. Dans ce but, nous avons étudié les effets de la DPDPE sur les taux extracellulaires de dopamine et de glutamate après lésion du cortex ipsilatéral. Nos résultats montrent que la libération striatale de dopamine induite par la DPDPE est la conséquence d'une libération de glutamate par les terminaisons cortico-striatales. Nous avons ensuite recherché une éventuelle contribution des cellules gliales à ce processus. Nos expériences indiquent que, bien qu'essentielles à l'homéostasie du glutamate, les cellules gliales ne participent pas aux effets stimulants de la DPDPE sur les taux de glutamate et de dopamine. Nous avons enfin étudié l'implication comportementale de ces interactions, grâce au modèle des dyskinésies induites par la L-DOPA chez le rat hémi-parkinsonien. Nos résultats montrent que les récepteurs δ portés par les terminaisons cortico-striatales sont impliqués dans ces dyskinésies. Nos travaux permettent ainsi d'élargir la connaissance des interactions entre les principaux systèmes de transmission du striatum. Ils confèrent également aux antagonistes des récepteurs δ d'intéressantes perspectives dans l'amélioration du traitement de la maladie de Parkinson.
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Effet de l’activation du récepteur mGluR2 par LY-354,740 sur les dyskinésies chez le modèle parkinsonien de rat lésé à la 6-hydroxydopamineFrouni, Imane 04 1900 (has links)
No description available.
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Deep brain stimulation : effects on swallowing function in Parkinson's diseaseKulneff, Linda, Sundstedt, Stina, Olofsson, Katarina, van Doorn, Jan, Linder, Jan, Nordh, Erik, Blomstedt, Patric January 2013 (has links)
Objective: In patients with Parkinson’s disease (PD), deep brainstimulation of the subthalamic nucleus (STN DBS) is well recognizedin improving limb function, but the outcome on swallowing functionhas rarely been studied. The aim of this work was to evaluate theeffect of STN DBS on pharyngeal swallowing function in patientswith PD using self-estimation and fiberoptic endoscopic evaluation ofswallowing. Methods: Eleven patients (aged 41–72, median 61 years)were evaluated preoperatively and at 6 and 12 months after STN DBSsurgery. All patients were evaluated with self-estimation on a visualanalogue scale, and eight of them with a fiberoptic endoscopicexamination with a predefined swallowing protocol includingRosenbek’s Penetration-Aspiration Scale, Secretion Severity Scale,preswallow spillage, pharyngeal residue, and pharyngeal clearance. Results: The self-assessments of swallowing function revealed asubjective improvement with STN DBS stimulation, whereas the datafrom the swallowing protocol did not show any significant effect ofthe STN DBS treatment itself. The prevalence of aspiration was notaffected by the surgery. Conclusions: The results show thatswallowing function was not negatively affected by STN DBS and therisk of aspiration did not increase. Self-estimation of swallowingfunction showed a subjective improvement due to stimulation / Speech, voice and swallowing outcomes after deep brain stimulation (DBS)
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Protective role of glutathione peroxidase against levodopa-induced cytotoxicity in PC12 cellsKim-Han, Jeong Sook, January 1998 (has links)
Thesis (Ph. D.)--University of Missouri--Columbia, 1998. / Typescript. Vita. Includes bibliographical references (leaves: 138-170). Also available on the Internet.
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Histamine H<sub>3</sub> Receptor Ligands Modulate L-Dopa-Evoked Behavioral Responses and L-Dopa-Derived Extracellular Dopamine in Dopamine-Denervated Rat StriatumNowak, Przemyslaw, Bortel, Aleksandra, Dabrowska, Joanna, Biedka, Izabela, Slomian, Grzegorz, Roczniak, Wojciech, Kostrzewa, Richard M., Brus, Ryszard 01 September 2008 (has links)
To explore a recently established association between histaminergic and dopaminergic neuronal phenotypic systems in brain, we determined the effect of the respective histaminergic H3 receptor agonist and antagonist/inverse agonist, imetit and thioperamide, on L-DOPA - derived tissue and extracellular dopamine (DA) and metabolite levels in the striatum of 6-hydroxydopamine (6-OHDA) - lesioned rats (i.e., parkinsonian rats). We also examined the influence of histamine H3 ligands on L-DOPA evoked behavioral responses (locomotor activity, number of rearings, stereotyped behavior and motor coordination). Using HPLC/ED and in vivo microdialysis technique, imetit (5 mg/kg, i.p.) but not thioperamide (5 mg/kg, i.p.) was shown to attenuate an L-DOPA-evoked (15 mg/ kg, i.p.; carbidopa, 30 min pretreatment) increase in extracellular DA in the neostriatum of 6-OHDA-lesioned rats. However, both imetit and thioperamide increased microdialysate levels of DOPAC and HVA, probably by enhancing intraneuronal DA utilization. As indicated by neurochemical analysis of the striatum imetit produced a decrease in tissue DA content. These findings support the hypothesis that central H3 histaminergic receptors have a modulatory role in the storage, metabolism and release of DA derived from exogenous L-DOPA challenge. Furthermore, evidence from behavioral studies indicate that histamine H3 receptor block markedly improved motor coordination. Conversely, histamine H3 receptor stimulation, being without effect on motor coordination, enhanced vertical activity in rats. From the above we conclude that histamine H3 agonism may augment motor dyskinesia in Parkinson's disease (PD) patients and presumably worsen L-DOPA therapy. Consequently, the histaminergic system represents a viable target for modulating the effectiveness of L-DOPA therapy in Parkinson's disease.
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INTRODUCTION OF NEGATIVELY CHARGED FUNCTIONALITIES INTO DOPA CONTAINING POLYMER MIMICSTaylor A Jones (9187493) 09 September 2022 (has links)
Many sticky denizens of the ocean use unique and effective techniques to stick together
and adhere to surfaces underwater. Underwater adhesion is a daunting task that many have set out
to solve. One of the key factors of underwater adhesion and focus of this dissertation will be on
negative charges and their role in underwater adhesion. Following previous work done on
poly[(3,4-dihydroxystyrene)-co-styrene], an adhesive mimic to mussel adhesives, new functional
groups were introduced to the same backbone to determine the change in adhesion in underwater
and dry conditions. These functional groups were mainly comprised of negatively charged
moieties such as sulfonates, phosphates, and phosphonates. Phosphates have been shown to exist
in mussel proteins alongside positively charged proteins.
A main facet of this dissertation will be focused on the specific synthesis pathways of
modified charged synthetic mimics of existing polymer systems both styrene and acrylic based.
Synthetic pathways were a challenging aspect of designing these polymers as functionalization
can add many steps to the synthesis of polymers which makes the process tedious and lengthy.
Characterization of these polymers were also important for determining the successful synthesis
of these functionalized polymers. Several reactions conducted from this research have not been
used on polymeric species and have been shown primarily in small organic molecules. Early work
on poly[(3,4-dihydroxystyrene)-co-styrene]-based sulfonates, phosphates, and phosphonates
established a foundation in pre and post functionalization of polymer species. Testing of adhesion,
exploration of functionalization and synthesis optimization were the main goals for each type of
functionalized polymer.
Following the tests of many poly[(3,4-dihydroxystyrene)-co-styrene] based functionalized
polymers it was shown that acrylic versions of phosphates performed substantially better for both
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dry and underwater adhesion, especially on SAE 304 stainless steel. The acrylic phosphate
polymers were based on previous DMA/MMA polymer systems that have shown to have excellent
adhesive potential. The phosphate monomer MAEP was introduced to the polymer structure,
which facilitated increased binding to steel substrates. Despite the acrylics overwhelmingly higher
adhesion compared to the functionalized poly[(3,4-dihydroxystyrene)-co-styrene] polymers the
phosphonate versions were shown to form a coacervate like material with positive charged
poly[(3,4-dihydroxystyrene)-co-styrene] mimics. These “coacervates” had appreciable adhesion,
much higher than the negative or positive versions had alone in dry conditions but despite this
could not retain their metastable coacervate phase in wet conditions. Further study is underway in
determining the role of negative charges in varying systems and determining whether adding
negative charge to a polymer system truly helps with underwater adhesion alone.
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Nur77 au sein des désordres dopaminergiques inhérents à la schizophrénie, la maladie de Parkinson ou la dépendance aux drogues d'abusBourhis, Emmanuelle 08 1900 (has links)
Cette thèse vise à mieux comprendre le rôle du facteur de transcription Nur77 au sein des fonctions physiologiques et pathologiques des voies de neurotransmission dopaminergiques des gaglions de la base. Nous basant sur une implication motrice de Nur77 au sein des dyskinésies induites à la L-DOPA (LIDs), nous avons voulu tester in vivo son implication éventuelle dans les phénomènes moteurs et de sensibilisation associés à l’amphétamine ainsi qu’une implication possible du récepteur nucléaire aux rétinoïdes RXR dont nous avons déjà démontré une implication dans les effets moteurs des antipsychotiques. Un deuxième volet de la recherche à consisté en l’étude de l’implication des extracellular signal-regulated kinase (ERK) et de la protéine kinase C (PKC) dans l’induction de l’ARNm des membres de la famille des Nurs suite à l’activation des cascades de signalisation des récepteurs dopamiergiques D1 et D2 in vivo pour une meilleure compréhension des mécanismes physiopatholoiques liés aux désordres dopaminergiques.
Pour ce faire, nous avons, premièrement, soumis des souris sauvages et Nur77-/- à un paradigme de sensibilisation à l’amphétamine ainsi qu’a différents agonistes antagonistes RAR/RXR afin de tester l’implication de Nur77 et d’un éventuel complexe Nur77/RXR dans les effets de l’amphétamine. Deuxièmement, soumis des souris sauvages à une combinaison d’agonistes D1/D2 ou une injection d’antagoniste D2 avec ou sans inhibiteur (ERK1/2 ou PKC) afin de tester l’implication de ces kinases sur l’induction de l’ARNm des membres de la famille des Nurs par hybridation in situ.
Nous avons ainsi pu démontrer 1- un rôle moteur de Nur77 dans les effets liés à l’amphétamine notamment avec une absence de stéréotypies et un allongement de la durée de la phase de locomotion chez les souris Nur77-/-; ainsi qu’un rôle éventuel du complexe potentiel Nur77/RXR dans les D1 à mieux définir. 2- un rôle des kinases ERKs et PKCs dans les cascades de signalisation des récepteurs dopaminergiques D1 et D2 menant à l’induction des ARNms de Nur77, Nor-1 et Nurr-1.
En perspective, ces résultats nous ouvrent la voie vers une implication éventuelle de Nur77 dans les mécanismes d’apprentissage que sont le Long Terme Potentiation (LTP) et la Long Terme Depotentialisation (LTD) liés aux LIDs et à l’amphétamine. / This thesis aims to better understand the role of the transcription factor Nur77 in the physiological and pathological functions of dopaminergic neurotransmission pathways of the basal gaglia. Based on a motor involvement of Nur77 in L-DOPA induced dyskinesias (LIDs), we wanted to test its possible involvement in the motor mechanisms associated with amphetamine, a drug of abuse that targets the direct neuronal population of the basal ganglia such as L-DOPA. Involvement of extracellular signal-regulated kinase (ERK) and protein kinase C (PKC) has been widely demonstrated in the LIDs and the effects of amphetamine, we wanted to know whether Nur77 mRNA was controlled by these kinases in both the striatonigral and striataux palidal neurons in response to specific activation of the D1 and D2 receptors in vivo. Finally, a possible involvement of RXR has been demonstrated in the motor effects of antipsychotic drugs, so we wanted to test its potential involvement in the effects of amphetamine.
To do this, we subjected wild-type mice and Nur77-/- mice to a paradigm of sensitization to amphetamine with or without RXR agonist (DHA) and antagonsite (HX531) to test: 1 - the involvement of Nur77 in the motor effects and the phenomenon of sensitization to amphetamine and 2 - the involvement of any complex Nur77/RXR in these effects. Second, wild-type mice were subjected to a combination of D1/D2 agonists or antagonists D2 with or without ERK inhibitor or PKC inhibitor to test in vivo the induction of the mRNA of the Nurs members family by in situ hybridization.
We were able to demonstrate a role of Nur77 in the motor effects associated with amphetamine namely in the absence of stereotypy and a lengthening of the duration of the phase of locomotion in Nur77-/ - mice; and a possible role of the potential complex Nur77/RXR in D1 neurones needed to be better defined. In addition, it is clearly demonstrated that the induction of Nurs members mRNA responds to the activation of signaling cascades of dopaminergic D1 or D2 receptors within the involvement of PKC and ERK kinases is undubtable which opens us the way to a possible involvement of Nur77 in learning mechanisms associated with LIDs and amphetamine that are the Long Terme Potentiation (LTP) and the Long Terme Depotentialisation (LTD).
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Biological Applications of Elastin- and Mussel-Inspired PolymersSydney E. Hollingshead (5929754) 03 January 2019 (has links)
<div>Wounds are created in soft and hard tissue through surgery or disease. As the wound heals, the tissue is held in place using sutures or staples for soft tissue or plates, pins, or screws for hard tissues. These fixation methods inherently damage the surrounding healthy tissue. Surgical adhesives are a non-damaging alternative to these methods. In order to be effective, surgical adhesives must be biocompatible,</div><div>adhere strongly in a moist environment, and have mechanical properties similar to those of the native tissue.</div><div><br></div><div><div>To address the design criteria for surgical adhesives, we look to nature to find inspiration from compounds that provide these properties. Mussels use catechol-based</div><div>molecules to adhere to surfaces in wet and turbulent environments. Incorporating catechols into polymer systems can provide adhesion even in moist biological environments.</div><div>Mimics of elastomeric proteins from soft tissue can be used as backbones for soft and flexible adhesive systems. In particular, elastin-inspired proteins have a well-defined modular sequence that allows for a range of design choices. In this work, we explored the behavior of elastin- and mussel-inspired natural and synthetic polymers in biologically relevant environments.</div></div><div><br></div><div><div>First, the cytocompatibility of a catechol-containing poly(lactic acid) (cPLA) hard tissue adhesive was studied. The cPLA polymer was reacted with iron- or periodatebased</div><div>crosslinkers and compared to PLA. Fibroblasts grown directly on cPLA or cultured with leachate from cPLA had high viability but slower growth than cells on PLA. The periodate crosslinker was significantly cytotoxic, and cells grown on cPLA crosslinked with periodate had reduced metabolism and slowed growth. Cells grown on or in leachate from iron-crosslinked cPLA had similar viability, metabolism, and growth to cells on or in leachate from cPLA. The iron-crosslinked cPLA is a promising</div><div>cytocompatible adhesive for hard tissue applications.</div></div><div><br></div><div><div>Second, two elastin-like proteins (ELP) were developed that had pH-sensitive properties in solution and when crosslinked into hydrogels. Both ELPs had a large number of ionizable tyrosine and lysine residues, and one design also had a large number of ionizable histidine and aspartic acid residues. The stiffness of the hydrogels was maximized at pH values near the isoelectric point of the protein. The stoichometric ratio of crosslinker used affected hydrogel stiffness but did not significantly alter the pH-sensitivity of the gel. The crosslinked gel shrank when swelled at physiological pH. The pH-sensitive mechanical properties of hydrogels made from the two ELPs did not vary significantly. The tyrosine and lysine residues in one ELP were also</div><div>chemically blocked through acetylation to lower the isolectric point of the protein. The acetylated hydrogels had maximum stiffness at a pH near the isoelectric point of the acetylated ELP. The stiffness of both the native and acetylated gels were within the range of soft tissue. Through a combination of crosslinker ratio and chemical modification, the pH-responsive properties of the elastin-inspired hydrogels could be tuned.</div></div><div><br></div><div><div>Finally, adhesive proteins were created that were inspired by both elastin and mussels. An ELP was modified to include catechol groups (mELP). The ELP and mELP were optimized for adhesive use in a soft tissue system. A warm and humid environment was used to study the adhesion of these proteins on pig skin. Iron and (hydroxymethyl) phosphine crosslinkers increased the adhesive strength of both proteins, and periodate increased the adhesive strength of mELP. The adhesive strengths of the proteins were maximized when mELP was mixed with iron or when either protein were mixed with (hydroxymethyl)phosphine crosslinkers. These maximized adhesives were 12-17 times stronger than a commercially available sealant. In addition,</div><div>the iron and mELP adhesive formulation achieved high adhesive strengths even when cured for only ten minutes. This adhesive formula shows promise for adhesive</div><div>applications on soft tissue.</div></div>
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Nur77 au sein des désordres dopaminergiques inhérents à la schizophrénie, la maladie de Parkinson ou la dépendance aux drogues d'abusBourhis, Emmanuelle 08 1900 (has links)
Cette thèse vise à mieux comprendre le rôle du facteur de transcription Nur77 au sein des fonctions physiologiques et pathologiques des voies de neurotransmission dopaminergiques des gaglions de la base. Nous basant sur une implication motrice de Nur77 au sein des dyskinésies induites à la L-DOPA (LIDs), nous avons voulu tester in vivo son implication éventuelle dans les phénomènes moteurs et de sensibilisation associés à l’amphétamine ainsi qu’une implication possible du récepteur nucléaire aux rétinoïdes RXR dont nous avons déjà démontré une implication dans les effets moteurs des antipsychotiques. Un deuxième volet de la recherche à consisté en l’étude de l’implication des extracellular signal-regulated kinase (ERK) et de la protéine kinase C (PKC) dans l’induction de l’ARNm des membres de la famille des Nurs suite à l’activation des cascades de signalisation des récepteurs dopamiergiques D1 et D2 in vivo pour une meilleure compréhension des mécanismes physiopatholoiques liés aux désordres dopaminergiques.
Pour ce faire, nous avons, premièrement, soumis des souris sauvages et Nur77-/- à un paradigme de sensibilisation à l’amphétamine ainsi qu’a différents agonistes antagonistes RAR/RXR afin de tester l’implication de Nur77 et d’un éventuel complexe Nur77/RXR dans les effets de l’amphétamine. Deuxièmement, soumis des souris sauvages à une combinaison d’agonistes D1/D2 ou une injection d’antagoniste D2 avec ou sans inhibiteur (ERK1/2 ou PKC) afin de tester l’implication de ces kinases sur l’induction de l’ARNm des membres de la famille des Nurs par hybridation in situ.
Nous avons ainsi pu démontrer 1- un rôle moteur de Nur77 dans les effets liés à l’amphétamine notamment avec une absence de stéréotypies et un allongement de la durée de la phase de locomotion chez les souris Nur77-/-; ainsi qu’un rôle éventuel du complexe potentiel Nur77/RXR dans les D1 à mieux définir. 2- un rôle des kinases ERKs et PKCs dans les cascades de signalisation des récepteurs dopaminergiques D1 et D2 menant à l’induction des ARNms de Nur77, Nor-1 et Nurr-1.
En perspective, ces résultats nous ouvrent la voie vers une implication éventuelle de Nur77 dans les mécanismes d’apprentissage que sont le Long Terme Potentiation (LTP) et la Long Terme Depotentialisation (LTD) liés aux LIDs et à l’amphétamine. / This thesis aims to better understand the role of the transcription factor Nur77 in the physiological and pathological functions of dopaminergic neurotransmission pathways of the basal gaglia. Based on a motor involvement of Nur77 in L-DOPA induced dyskinesias (LIDs), we wanted to test its possible involvement in the motor mechanisms associated with amphetamine, a drug of abuse that targets the direct neuronal population of the basal ganglia such as L-DOPA. Involvement of extracellular signal-regulated kinase (ERK) and protein kinase C (PKC) has been widely demonstrated in the LIDs and the effects of amphetamine, we wanted to know whether Nur77 mRNA was controlled by these kinases in both the striatonigral and striataux palidal neurons in response to specific activation of the D1 and D2 receptors in vivo. Finally, a possible involvement of RXR has been demonstrated in the motor effects of antipsychotic drugs, so we wanted to test its potential involvement in the effects of amphetamine.
To do this, we subjected wild-type mice and Nur77-/- mice to a paradigm of sensitization to amphetamine with or without RXR agonist (DHA) and antagonsite (HX531) to test: 1 - the involvement of Nur77 in the motor effects and the phenomenon of sensitization to amphetamine and 2 - the involvement of any complex Nur77/RXR in these effects. Second, wild-type mice were subjected to a combination of D1/D2 agonists or antagonists D2 with or without ERK inhibitor or PKC inhibitor to test in vivo the induction of the mRNA of the Nurs members family by in situ hybridization.
We were able to demonstrate a role of Nur77 in the motor effects associated with amphetamine namely in the absence of stereotypy and a lengthening of the duration of the phase of locomotion in Nur77-/ - mice; and a possible role of the potential complex Nur77/RXR in D1 neurones needed to be better defined. In addition, it is clearly demonstrated that the induction of Nurs members mRNA responds to the activation of signaling cascades of dopaminergic D1 or D2 receptors within the involvement of PKC and ERK kinases is undubtable which opens us the way to a possible involvement of Nur77 in learning mechanisms associated with LIDs and amphetamine that are the Long Terme Potentiation (LTP) and the Long Terme Depotentialisation (LTD).
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