COCAINE & NICOTINE ACTION ON CNS ACETYLCHOLINE RECEPTORS

描述(申请人摘要)： 这个项目的目标是确定分子机制， 两种滥用药物尼古丁和可卡因与神经元尼古丁相互作用 外周和中枢的乙酰胆碱受体(NAChRs) 系统。可卡因通过多巴胺发挥其愉悦、上瘾的性质。 运输系统，但它的一些毒性作用可能通过一些 神经元nAChRs亚型。NAChRs调节信号在 许多中枢神经系统神经元和神经肌肉连接处，以及 尼古丁和可卡因都会影响它们的功能。文献中的报道 都认为可卡因和其他局部麻醉剂在给药时 在脑室内，对行为和药理学有拮抗作用 尼古丁的影响。这项建议的目的是确定化学物质 尼古丁激活和可卡因抑制神经元的机制 NAChRs在非洲爪哇卵母细胞中表达。初步结果表明 不同的神经元尼古丁受体亚型是不同的 受可卡因影响。可卡因对某些神经元亚型的亲和力是 在预期存在的可卡因浓度范围内 在可卡因过量期间，可能在娱乐使用期间 可卡因。因此，特定的尼古丁受体亚型可能会发挥作用 在可卡因的毒性中扮演了一个角色。可卡因与野生动物结合的地方 类型和突变的nAChRs将在功能和化学上进行表征。 所采用的方法包括：(I)构建不同类型的受体 亚基组成、嵌合体和多肽区域改变的亚基 定点突变，以及(Ii)使用一种新的 由我们的实验室开发的技术，时间为50到100微秒 一种决议，使人们能够确定药物对 受体介导的反应的基本步骤。分子 机制，包括尼古丁和尼古丁的浓度 可卡因影响特异性nAChRs，将为基于机制的研究提供基础 设计可减轻药物某些作用的治疗剂 而不会产生有害的影响。所获得的知识是 预计将有助于合理对待数百万 受到可卡因和尼古丁不利影响的个人。

DESCRIPTION (Applicant's Abstract): The goal of this project is to determine the molecular mechanism by which two abused drugs, nicotine and cocaine, interact with neuronal nicotinic acetylcholine receptors (nAChRs) in the peripheral and central nervous systems. Cocaine exerts its euphoric, addictive nature through the dopamine transport system, but some of its toxic effects may occur by way of some subtypes of neuronal nAChRs. nAChRs regulate signal transmission between many central nervous system neurons and at the neuromuscular junction, and both nicotine and cocaine affect their function. Reports in the literature have suggested that cocaine and other local anesthetics, when administered intraventricularly, are antagonistic to the behavioral and pharmacological effects of nicotine. The aim of this proposal is to determine the chemical mechanism of by which nicotine activates and cocaine inhibits neuronal nAChRs expressed in Xenopus oocytes. Preliminary results have demonstrated that different neuronal nicotinic receptor subtypes are differentially affected by cocaine. The affinity of cocaine for some neuronal subtypes is well within the range of concentrations of cocaine expected to be present during a cocaine overdose and, possibly, during the recreational use of cocaine. Thus specific nicotinic receptor subtypes may be expected to play a role in the toxicity of cocaine. The site to which cocaine binds on wild type and mutated nAChRs will be characterized functionally and chemically. The approaches adopted include (I) construction of receptors with varying subunit composition, chimeras, and subunits with peptide regions altered by site-directed mutations, and (ii) chemical kinetic measurements using a new technique developed by our laboratories, with a 50 to 100 micro-second time resolution that allows one to determine the effect of the drugs on the elementary steps of the receptor mediated reactions. The molecular mechanism, including knowledge of the concentraton at which nicotine and cocaine affect specific nAChRs, will provide a basis for mechanism-based design of therapeutic agents that will alleviate some effects of the drugs without themselves having deleterious effects. The knowledge gained is expected to contribute to the rational treatment of the millions of individuals adversely affected by cocaine and nicotine.