REGULATION OF NEURAL ACETYLCHOLINE RECEPTORS

除了将化学信号转化为 电反应，神经递质门控离子通道， 是动态的分子实体，受其 在很宽的时间范围内响应。 的重点 本提案中描述的实验是关于 调节PC 12细胞的神经乙酰胆碱受体（AcChR）， 克隆交感神经细胞系。 激动剂- 通过钠内流检查介导的脱敏 受体活性的测量。 的可能性 磷酸化-去磷酸化反应参与了 长期脱敏的发展，其特征在于 缓慢的发病率和恢复率，将通过获得 同时测量AcChR的范围 磷酸化 定量PC 12的nAcChR的结合测定 细胞将被开发，以检查是否失活， 激动剂诱导的产生不可逆免疫的过程 渗透率响应，涉及表面的快速损失 受体。 失活与生物活性的关系 将通过以下方法检查涉及脱敏的受体状态： 动力学分析对这些速率的影响 不同的胆碱能拮抗剂。 其他人的作用 细胞外的突触成分，例如P物质，和 细胞内，例如Ca 2+和cAMP，在进一步调节这些 激动剂介导的过程也将通过相同的方法进行评价。 生化技术 通过研究短期和长期监管机制， nAcChR的激动剂和其他突触成分， 拟议的研究将有助于评估 调节突触效能的突触后机制。 一 更好地了解这些过程将有助于阐明 大脑最显著的特性： 受经验的制约。

In addition to their ability to convert chemical signals into electrical responses, neurotransmitter-gated ion channels, they are dynamic molecular entities, subject to regulation of their responsiveness over a wide temporal range. The focus of the experiments described in this proposal is on the mechanisms that regulate the neural acetylcholine receptor (AcChR) of PC12 cells, a clonal sympathetic cell line. The kinetic properties of agonist- mediated desensitization will be examined by sodium influx measurements of receptor activity. The possibility that phosphorylation-dephosphorylation reactions are involved in the development of long lasting desensitization that is characterized by slow onset and recovery rates, will be investigated by obtaining measurements, in parallel, of the extent of AcChR phosphorylation. A binding assay to quantitate nAcChRs of PC12 cells will be developed to examine whether deactivation, an agonist-induced process that produces an irreversible dimunution of the permeability response, involves a rapid loss of surface receptors. The relationship between deactivation and the receptor states involved in desensitization will be examined by kinetic analysis of the effects on the rates of each of these processes by different cholinergic antagonists. The role of other synaptic components both extracellular, e.g. substance P, and intracellular, e.g. Ca2+ and cAMP, in modulating further these agonist-mediated processes will also be evaluated by the same biochemical techniques. By examining the mechanisms of short- and long-term regulation of nAcChR by agonists and other synaptic components, the proposed studies will aid in evaluating the possible role of postsynaptic mechanisms in modulating synaptic efficacy. A better understanding of these processes will shed light on one of the most remarkable properties of the brain: its ability to be regulated by experience.