ANESTHETIC MECHANISMS IN CLONED NICOTINIC AND GABA A RECEPTORS

本建议书是一项新计划项目赠款的项目III “配基门控离子通道上的全麻药部位。”从长远来看 这个项目的目标是定义全身麻醉的方式和地点。 药物调节神经递质门控离子通道的功能 大脑。此信息对于设计更安全的常规应用程序至关重要 麻醉剂。工作假说是麻醉剂通过结合到 同源“环”配体门控超家族上的疏水位点 包括烟碱型乙酰胆碱受体(NAChRs)和 γ-氨基丁酸受体(GABAAR)。这项提案集中在这两个方面 NAChRs和GABAARs，因为麻醉药在nAChRs和GABAARs中的作用 显示相似之处；抑制和增强都可以观察到，这取决于 关于受体状态和麻醉药。NAChR是一种 麻醉剂的结构、功能和机制的实验模型 与其他离子通道相比，动作定义得更好。GABAAR是 可能是全麻药的临床重要靶点 大脑。具体目标1是定义哪些运动状态(休息、打开或 NAChR和GABAAR受麻醉药影响。 重组、表达nAChR和GABAAR受体与快速灌流 模拟自然突触的电生理学技术将被用于 研究抑制剂和增效剂的作用。具体目标2是 为了确定nAChR蛋白的光标记区域 通过麻醉剂(PPG项目I和II)形成结合部位 麻醉剂会导致它们不同的作用。一个独立的站点，其中 麻醉剂阻断开放的nAChR孔，已被鉴定并部分 已映射。通过突变重组人的其他麻醉剂结合区 NAChRs，详细说明麻醉剂在哪里起作用的特定模型将进行测试。 具体目标3是确定GABAAR抑制和增强 这些部位是由与麻醉剂结合的区域同源形成的 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.