ETIOLOGIC PATHWAYS TO DOPAMINE DYSFUNCTION

该Conte Center申请的前提是，皮质多巴胺能突触功能的破坏是精神分裂症的最终共同途径，表现为精神分裂症相关行为、多巴胺失衡内表型和脑结构/功能的发作性畸变。该项目的目标是生成具有合理病因的小鼠模型，并询问这些模型是否与复制接受脑成像的患者中所见的多巴胺能和多巴胺能异常有关。该模型是一个例子，定时中断大脑皮层发育，管理的神经元DNA甲基化剂甲基偶氮甲醇乙酸（MAM）在妊娠第16天，一个链接验证的神经发育模型，NRG 1杂合子敲低，和一个微妙的突触前皮质神经元能缺陷，限制性敲低或敲除谷氨酸合成酶磷酸激活的转氨酶。将研究这些机制上不同的小鼠模型，以确定以下目标：目标1。多巴胺系统的改变，在急性和致敏范式，基线和安非他明刺激的多巴胺流出在纹状体和额叶皮质中使用体内微透析，多巴胺受体表达，多巴胺能神经支配的酪氨酸羟化酶阳性纤维的体视学定量，和异常的表达由多巴胺调节的基因在纹状体和皮质的行为反应。目标2.皮质中的谷氨酸能改变，观察额叶-皮质依赖性认知/行为功能，使用MRI观察总体形态和活动的变化，使用微阵列技术观察突触相关基因表达，通过rt-PCR和配体结合观察NMDA受体表达，以及谷氨酸能突触传递和可塑性。目标3.谷氨酸受体激活或直接刺激额叶皮质影响多巴胺神经元放电和多巴胺流出。目标4。精神分裂症相关改变的发展，观察断奶前和青春期的年轻小鼠，以验证精神分裂症相关发现的青春期发作。总之，本项目中的小鼠模型以及Kandel项目中的小鼠模型应确定精神分裂症发病机制中可能的最终共同途径，该途径可以在小鼠中进行最有效的分析，研究涵盖行为，化学，生理学和基因表达。由于候选基因可以通过与临床数据的相关性来验证，新的治疗方向应该变得明显。

The premise of this Conte Center application is that cortical disruption of glutamatergic synaptic function is the final common pathway in schizophrenia, manifesting in schizophrenia-associated behaviors, a dopamine-imbalance endophenotypes and adolescent-onset aberrations in brain structure/function. The goal of this project is to generate mouse models with a plausible etiology, and to ask whether the models are associated with dopaminergic and glutamatergic abnormalities replicating those seen in patients undergoing brain imaging. The models are an example of timed disruption of cerebral cortical development, administration of the neuronal DNA-methylating agent methylazoxymethanol acetate (MAM) at gestational day 16, a linkage-validated neurodevelopmental model, the NRG1 heterozygote knockdown, and a subtle presynaptic cortical glutamatergic deficit, a restricted knockdown or knockout of the glutamate-synthetic enzyme phosphate-activated glutaminase. These mechanistically distinct mouse models will be studied in concert with the goal of identifying: Aim 1. Dopamine system alterations, looking at the behavioral response to dopaminergic agonists in acute and sensitization paradigms, baseline and amphetamine-stimulated dopamine efflux in the striatum and frontal cortex using in vivo microdialysis, dopamine receptor expression, dopaminergic innervation of stereological quantification of tyrosine hydroxylase-positive fibers, and abnormalities in expression of genes regulated by dopamine in striatum and cortex. Aim 2. Glutamatergic alterations in cortex, looking at frontal-cortical dependent cognitive/behavioral functions, changes in gross morphology and activity using MRI, synapse-associated gene expression using microarray technology, NMDA receptor expression by rt-PCR and by ligand binding, and glutamatergic synaptic transmission and plasticity. Aim 3. glutamate receptor activation or direct stimulation of the frontal cortex affect dopamine neuron firing and dopamine efflux. Aim 4. Development of schizophrenia-associated alterations, looking at young mice prior to weaning and in adolescence, to verify adolescent onset of schizophrenia associated findings. Taken together, the mouse models in this Project together with those in Project by Kandel should identify a possible final common pathway in the pathogenesis of schizophrenia, which can be most effectively analyzed in mice with studies spanning behavior, chemistry, physiology and gene expression. As candidate genes can be validated by correlations with clinical data, new therapeutic directions should become evident.