ANESTHETIC MECHANISMS IN CLONED NICOTINIC AND GABA A RECEPTORS

该提案是一项新的计划项目赠款的项目III， “配体门控离子通道上的全身麻醉位点。“长期而言， 本项目的目的是确定如何以及在何处全身麻醉 药物调节神经递质门控离子通道的功能， 个脑袋这些信息对于设计更安全的通用 麻醉剂工作假设是，麻醉剂通过结合 同源“cys环”配体门控超家族上的疏水位点 离子通道，包括烟碱乙酰胆碱受体（nAChR）和 γ-氨基丁酸受体（GABAAR）。该提案侧重于两个方面 nAChR和GABAAR，因为麻醉剂在nAChR和GABAAR中的作用 显示平行;观察到抑制和增强，取决于 对受体状态和麻醉药的影响。nAChR是一种 麻醉剂的结构、功能和机制的实验模型 作用比其它离子通道的作用更好地定义。GABAAR是 可能是全身麻醉药的临床重要靶点， 个脑袋具体目标1是定义哪些动力学状态（静息、开放或 nAChR和GABAAR的脱敏）受到麻醉剂的影响。 重组表达的nAChR和GABAAR受体和快速灌注 模拟自然突触的电生理学技术将用于 研究抑制剂和增效剂的作用。具体目标2是 为了确定nAChR蛋白的被光标记的区域 通过麻醉剂（PPG项目I和II）形成结合位点， 麻醉剂引起它们的各种作用。一个独立的站点， 麻醉剂阻断开放的nAChR孔，已被确定和部分 映射。通过突变重组体中的其他麻醉剂结合区， nAChR，将测试详细说明麻醉剂作用位置的特定模型。 具体目标3是确定GABAAR抑制和增强是否 位点由与麻醉剂结合的区域同源的区域形成， nAChR

This proposal is Project III of a new Program Project Grant entitled "General Anesthetic Sites on Ligand gated Ion Channels." The long term objective of this project is to define how and where general anesthetic drugs modulate the function of neurotransmitter-gated ion channels in the brain. This information is essential for designing safer general anesthetics. The working hypothesis is that anesthetics act by binding to hydrophobic sites on the superfamily of homologous "cys-loop" ligand-gated ion channels that includes nicotinic acetylcholine receptors (nAChRs) and gamma-aminobutyric acid receptors (GABAAR). This proposal focuses on both nAChRs and GABAARs, because actions of anesthetics in nAChRs and GABAARs show parallels; both inhibition and potentiation are observed, depending on the receptor state and the anesthetic drug. The nAChR is an experimental model where structure, function, and mechanisms of anesthetic actions are better defined than those for other ion channels. GABAARs are likely to be clinically important targets for general anesthetics in the brain. Specific Aim 1 is to define which kinetic states (resting, open, or desensitized) of nAChR and GABAAR are affected by anesthetics. Recombinant, expressed nAChR and GABAAR receptors and rapid-perfusion electrophysiology techniques that mimic natural synapses will be used to study the actions of both inhibitors and potentiators. Specific Aim 2 is to determine whether regions of the nAChR protein that are photo-labeled by anesthetics (PPG projects I and II) form binding sites where anesthetics cause their various actions. One discrete site, where anesthetics block the open nAChR pore, has been identified and partially mapped. By mutating other anesthetic binding regions in recombinant nAChRs, specific models detailing where anesthetics act will be tested. Specific Aim 3 is to determine whether GABAAR inhibition and potentiation sites are formed by regions homologous to those where anesthetics bind to the nAChR.