ELECTROPHYSIOLOGICAL ANALYSIS OF NEUROTRANSMISSION

神经传递的电生理分析

• 批准号: 2264167
• 负责人: CRAIG E JAHR
• 金额: $ 16.51万
• 依托单位: OREGON HEALTH & SCIENCE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 1987
• 资助国家: 美国
• 起止时间: 1987-09-01 至 1997-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/2264167
• 关键词: NMDA receptors; clearance rate; electrophysiology; excitatory aminoacid; flash photolysis; glutamates; immunocytochemistry; laboratory rat; membrane channels; mixed tissue /cell culture; neural conduction; neural transmission; neurotransmitter transport; receptor binding; synapses; synaptogenesis; voltage /patch clamp

It is now generally accepted that excitatory transmission in many areas of the mammalian CNS depends on presynaptic release of L-glutamate and subsequent activation of at least two classes of glutamate-gated ion channels in postsynaptic neurons. AMPA (or non-NMDA) receptor channels mediate a very quickly activating and deactivating conductance that is responsible for most information transfer on the millisecond time scale. NMDA receptors have much slower kinetics and are required during synaptogenesis for the formation of appropriate connections and, in many excitatory pathways, for altering the strength of synaptic transmission. Although some of the underlying properties that govern the behavior of AMPA and NMDA receptors are known, very little is known about the basic mechanisms of excitatory synaptic activation. The objective of the proposed work is to characterize these basic phenomena: 1) how long free glutamate remains elevated in the synaptic cleft after presynaptic release, 2) how the time course of unbound transmitter concentration can be altered by processes that change the probability of release, 3) how the time course of unbound transmitter is affected by changing the efficacy of the mechanisms responsible for transmitter clearance, and finally, 4) how such alterations affect receptor occupancy and the frequency of channel opening. Knowledge of these basic phenomena in normal conditions is essential to understand 1) how synaptic release at one site may affect responses to subsequent or adjacent events, 2) what mechanisms are available for changing synaptic efficacy in both the short and long term, and 3) how pathological states such as stroke and epilepsy might affect synaptic processing at sites peripheral to those directly affected. We will use patch clamp and rapid solution exchange techniques to study NMDA and AMPA channel kinetics in isolated patches of membrane and single and dual whole cell recording to study autaptic and synaptic mechanisms. In addition, several techniques to isolate responses from individual synaptic contacts will be used to simplify the interpretation of results from whole cell synaptic events.

现在人们普遍认为，许多领域的兴奋性传播 哺乳动物中枢神经系统的依赖于l-谷氨酸和l-谷氨酸的突触前释放 随后至少激活两类谷氨酸门控离子 突触后神经元中的通道。 AMPA（或非NMDA）受体通道 调解非常快速的激活和停用电导 负责大多数信息转移以毫秒的时间尺度。 NMDA受体的动力学较慢，并且需要 用于形成适当连接的突触发生，在许多人中 激发途径，以改变突触传播的强度。 尽管某些控制行为的基础属性 已知AMPA和NMDA受体，对基本知识知之甚少 兴奋性突触激活的机制。目的 拟议的工作是表征这些基本现象：1）免费多长时间 谷氨酸在突触前突触中保持升高 释放，2）未结合发射器浓度的时间过程如何 通过改变发布概率的过程来改变，3） 未结合发射器的时间过程会因更改 负责发射机清除机制的功效，以及 最后，4）这种改变如何影响受体占用和 通道打开的频率。 了解这些基本现象 正常条件对于了解1）突触释放如何 一个站点可能会影响对随后或相邻事件的反应，2） 在短短的两个方面，机制可用于更改突触功效 长期和3）诸如中风和癫痫等病理状态如何 可能会影响直接对位置的站点的突触处理 做作的。 我们将使用补丁夹和快速解决方案交换技术 研究隔离膜斑块中的NMDA和AMPA通道动力学 以及单细胞记录以研究自动和突触的单细胞记录 机制。 此外，从隔离响应中的几种技术 个人突触接触将用于简化解释 全细胞突触事件的结果。