Glutamate-dopamine plasticity in nigrostriatal injury

描述(申请人提供)：MPTP损伤的小鼠是研究基底节损伤后纹状体多巴胺回归机制的极佳模型。给C57BL/6小鼠注射MPTP可导致黑质纹状体多巴胺能神经元的破坏和纹状体多巴胺的耗竭。MPTP损伤的一个优点是可以滴定神经细胞死亡的程度，以便剩余的多巴胺能神经元可以作为修复和恢复损伤反应的模板。我们的假设是，谷氨酸通过改变AMPA受体亚型的表达，激活转录因子磷酸化CREB，并导致存活的黑质纹状体多巴胺能神经元中酪氨酸羟化酶表达增加和轴突萌发。这项研究旨在确定MPTP损伤后AMPA受体(包括其磷酸化状态)、转录因子CREB、多巴胺受体(DL、D2和D3)以及生长相关蛋白GAP-43表达的变化。用AMPA受体拮抗剂GYKI-52466阻断谷氨酸神经传递对这些参数的影响将被确定。将使用免疫细胞化学、免疫印迹、原位杂交和顺行标记等分子工具来确定纹状体多巴胺返回的机制。这些研究的长期目标是阐明脑损伤后的可塑性特征，并确定治疗包括帕金森氏病、阿尔茨海默病和衰老在内的神经退行性疾病的新的治疗干预措施。

DESCRIPTION (provided by applicant): The MPTP-lesioned mouse serves as an excellent model to study the mechanisms involved in the return of striatal dopamine after basal ganglia injury. The administration of MPTP to C57BL/6 mice leads to the destruction of nigrostriatal dopaminergic neurons and subsequent depletion of striatal dopamine. An advantage of MPTP-lesioning is that the degree of neuronal cell death can be titrated such that remaining dopaminergic neurons may act as a template for repair and recovery in response to the injury. Our hypothesis is that glutamate, acting through altered expression of the AMPA-subtype of receptor, activates the transcription factor phospho-CREB and leads to increased tyrosine hydroxylase expression and axonal sprouting in surviving nigrostriatal dopaminergic neurons. This research proposal is designed to define changes that take place after MPTP injury in the expression of AMPA receptors (including their phosphorylated state), the transcription factor CREB, dopamine receptors (Dl, D2, and D3), and the growth-associated protein GAP-43. The effect of blocking glutamate neurotransmission with the AMPA receptor antagonist GYKI-52466 on these parameters will be determined. The molecular tools of immunocytochemistry, western immunoblotting, in situ hybridization, and anterograde labeling will be used to define the mechanisms involved in the return of striatal dopamine. The long-term goal of these studies is to elucidate features of plasticity following injury to the brain and to identify new therapeutic interventions for the treatment of neurodegenerative diseases including Parkinson's disease, Alzheimer's disease, and aging.