STUDIES OF PRE- AND POSTSYNAPTIC DOPAMINE PHYSIOLOGY IN THE BASAL GANGLIA

基底节突触前和突触后多巴胺生理学的研究

• 批准号: 3738132
• 负责人: GREG A GERHARDT
• 金额: --
• 依托单位: UNIVERSITY OF COLORADO DENVER
• 依托单位国家: 美国
• 资助国家: 美国
• 起止时间: 至
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/3738132
• 关键词: 6 hydroxydopamine; Parkinson's disease; anesthesiology; basal ganglia; behavior test; caudate nucleus; corpus striatum; denervation; diffusion; disease /disorder model; dopamine; dopamine agonists; dopamine receptor; electrochemistry; electrophysiology; electrostimulus; high performance liquid chromatography; laboratory rat; microdialysis; microelectrodes; neural transmission; neurogenesis; neurons; neuropharmacology; oxidation reduction reaction; receptor expression; receptor sensitivity; stereotaxic techniques; substantia nigra; synapses

The assessment of dopaminergic neurotransmission at both the presynaptic and postsynaptic level by in vivo electrochemical and electrophysiological manes, has been the object of investigation in our laboratory during the previous funding period. We intend to continue these investigations and address basic questions about presynaptic and postsynaptic dopaminergic mechanisms. First, high-speed chronoamperometric measures will be used to compare dopamine (DA) diffusion and clearance in normal and unilateral 6- OHDA-lesioned striatum. Our preliminary data suggest a much more extensive diffusion of DA in denervated striatum. In addition, using electrophysiological techniques, we will determine if denervation alters the relative effects of D1 and D2 receptors on caudate neurons as part of the induction of supersensitivity. Secondly, electrochemical methods using Nafion-coated recording electrodes will be used to measure the magnitude and temporal dynamics of potassium-evoked or electrically-induced release of DA in unanesthetized freely-moving animals, for comparison with the data obtained from anesthetized animals. Third, we will continue our ongoing electrophysiological characterization of the differential effects of D1 and D2 receptor activation, with attention both to intracellular transduction and ionic mechanisms and also to effects on both spontaneous and synaptic evoked activity. The role of different second messenger systems in D1 and D2 postsynaptic responses will also be elucidated by pertussis toxin inactivation of certain G-proteins. In addition, the effects of D1 and D2 receptor activation on the potassium-evoked overflow of DA will be measured using in vivo electrochemistry. Finally, the effects of chronic administration of DA agonists to presynaptic and postsynaptic elements in both normal and 6-OHDA lesioned animals will be investigated using electrophysiological, electrochemical and brain microdialysis methods. These experiments will lead to a better understanding of dopamine physiology in the intact and denervated caudate nucleus. Our efforts play two roles in this program project: (1) our in vivo electrochemical measurements of the function of the presynaptic dopaminergic nerve terminal and the electrophysiological assessment of postsynaptic responses to DA will be used by investigators in other projects to assess the function of transplants, and (2) our data from normal, 6-OHDA lesioned, and chronically treated animals will be used as a standard of comparison for the quantitative assessment of the recovery of function from various transplantation operations. Thus, this project will contribute to both the methodology and the data analysis of this program project.

突触前和突触后多巴胺能神经传递的评估 和突触后水平通过在体内电化学和电生理 鬃毛，一直是在我们的实验室调查的对象， 上一个融资期。 我们打算继续这些调查， 解决突触前和突触后多巴胺能神经元 机制等 首先，高速计时电流测量将用于 比较正常和单侧6- OHDA损伤的纹状体。 我们的初步数据表明， DA在失神经纹状体的扩散。 此外，使用 电生理技术，我们将确定是否去神经改变 D1和D2受体对尾状核神经元的相对作用， 超敏感性的诱导。 第二，电化学方法， Nafion涂层的记录电极将被用来测量幅度 钾诱发或电诱导释放的时间动态 DA在未麻醉的自由移动的动物，与数据进行比较 从麻醉的动物中获得。 第三，我们将继续我们的 D1和D2的差异效应的电生理学表征 D2受体活化，同时关注细胞内转导 和离子机制，以及对自发和突触 诱发活动。 不同的第二信使系统在D1和 D2突触后反应也将由百日咳毒素阐明 某些G蛋白的失活。 此外，D1和D2的作用 将测量钾诱发的DA溢出的受体活化 使用体内电化学。 最后，慢性病的影响 多巴胺激动剂给药突触前和突触后元件， 正常和6-OHDA损伤的动物都将使用 电生理学、电化学和脑微透析方法。 这些实验将使我们更好地了解多巴胺 完整和去神经尾状核的生理学。 我们的努力在这个项目中扮演了两个角色：（1）我们的体内 突触前神经元功能的电化学测量 多巴胺能神经末梢和电生理评价 研究者将在其他研究中使用对DA的突触后反应。 评估移植功能的项目，以及（2）我们的数据 正常、6-OHDA损伤和长期治疗的动物将用作 回收率定量评估的比较标准 各种移植手术的功能。 因此，该项目将 有助于这一计划的方法和数据分析 项目