MODULATION OF NEURONAL ACETYLCHOLINE RECEPTORS

神经元乙酰胆碱受体的调节

• 批准号: 2431142
• 负责人: Lorna W Role
• 金额: $ 29.97万
• 依托单位: COLUMBIA UNIVERSITY HEALTH SCIENCES
• 依托单位国家: 美国
• 财政年份: 1985
• 资助国家: 美国
• 起止时间: 1985-07-01 至 2000-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/2431142
• 关键词: Xenopus oocyte; acetylcholine; antisense nucleic acid; autoradiography; calcitonin gene related peptide; calcium flux; complementary DNA; evoked potentials; in situ hybridization; neural plasticity; neural transmission; neurotransmitter transport; nicotine; nicotinic receptors; polymerase chain reaction; prostaglandin E; protein kinase A; protein kinase C; protein structure function; receptor expression; second messengers; substance P; synapses; voltage /patch clamp

Recent molecular and biophysical studies of neuronal nicotinic acetylcholine receptors (nAChRs) have unveiled a rich diversity in both primary structure and function. While this diversity is certainly impressive, it is essential to determine why there so many distinct types of ACHR channels expressed by both central and peripheral neurons. The overall goal of this proposal is to test the hypothesis that a major physiological role of nAChR diversity is to allow selective modulation of particular nAChR subtypes in the control of synaptic transmission. This proposal converges on three aspects of nAChR channel modulation: the role of second messengers in nAChR modulation, the role of calcium in nAChR channel function and the physiological impact of nAChRs in the modulation of transmitter release at inter-neuronal synapses. We will examine the contribution of distinct nAChR channel subtypes and subunits to each of these modulatory phenomena in experiments addressing the following questions: 1: Do nAChR channel subtypes and subunits differ in their modulation by protein kinase C (activated by SP) and protein kinase A (by CGRP)? 2: Do nAChRs differ in their permeability to Ca and in their susceptibility to modulation by Ca? 3: What is the role of distinct nAChR subtypes and subunits in nicotine-mediated presynaptic facilitation? The proposed experiments employ both biophysical and molecular approaches. First, the modulation of native nAChRs will be examined by single channel recording. Then, the role of individual subunits in nAChR modulation will be assessed by selective subunit deletion with sequence specific antisense oligonucleotidls, The effects of subunit deletion on nAChR modulation will be assayed at the whole cell and single channel level. Finally, these experiments will be complemented by more traditional "combinatorial" approaches, examining the modulation of nAChRs expressed from mixtures of specific subunit cDNAs in Xenopus oocytes. Together these studies will determine both the channel subtype and nAChR subunit specificity of modulation and will examine receptor modulation from the molecular mechanisms to the physiological impact on transmitter release at an identified synapse. Detailed understanding of nAChRs is essential both because of the role of nAChRs in neural transmission and because of their status as prototypical ligand-gated channels. Thus, nAChRs at ganglionic synapses control numerous peripheral autonomic functions including the maintenance of vascular tone and hence, the regulation of blood pressure. Furthermore, the structural and functional diversity of nAChRs is common to all ligand-gated ion channels cloned to date, so that these studies will extend our understanding of the mechanisms underlying plasticity of transmitter-gated channels throughout the nervous system.

神经元烟碱的最近分子和生物物理研究 乙酰胆碱受体（NACHRS）在两者中都揭示了丰富的多样性 主要结构和功能。 虽然这种多样性肯定是 令人印象深刻的是，必须确定为什么有这么多不同类型 由中央和周围神经元表达的ACHR通道。 这 该提案的总体目标是检验一个主要的假设 NACHR多样性的生理作用是允许选择性调节 在控制突触传播中的特定NACHR亚型。 该建议在NACHR通道调制的三个方面收敛： 第二使者在NACHR调制中的作用，钙在 NACHR通道功能和NACHR的生理影响 在神经间突触下发射机释放的调制。 我们将 检查不同的NACHR通道亚型和亚基的贡献 在实验中，这些调节现象中的每一个 以下问题： 1：nACHR通道亚型和亚基的调制不同 蛋白激酶C（被SP激活）和蛋白激酶A（由CGRP激活）？ 2：nachrs对CA及其渗透性有所不同 CA对调节的敏感性？ 3：独特的NACHR亚型和亚基在 尼古丁介导的突触前促进？ 提出的实验采用生物物理和分子 方法。 首先，将对本机NACHR的调制进行检查 单个通道记录。 然后，单个亚基在NACHR中的作用 调制将通过序列的选择性亚基删除来评估 特定的反义寡核苷酸，亚基缺失对 NACHR调制将在整个单元格和单个通道上进行测定 等级。 最后，这些实验将得到更多的补充 传统的“组合”方法，检查了 NACHR从异武士中特定亚基cDNA的混合物表达 卵母细胞。 这些研究将共同​​确定频道亚型 调制的NACHR亚基特异性，并将检查受体 从分子机制到生理影响的调节 发射机在确定的突触处释放。 对NACHRS的详细了解既是必不可少的 NACHR在神经传播中的 原型配体门控通道。 因此，神经节突触处的nachrs 控制许多包括维护在内的外围自主功能 血管张力，因此是血压的调节。 此外，NACHR的结构和功能多样性很常见 到迄今为止克隆的所有配体门控离子通道，以便这些研究 将扩展我们对机制的理解 整个神经系统的发射机门控通道。