Molecular interactions of general anesthetics in voltage-gated sodium channels

尽管全身麻醉药的使用无处不在，但全身麻醉的分子基础尚未阐明。这项研究的长期目标是阐明全身麻醉作用的分子基础，这可能为设计更安全的全身麻醉药提供新的机会。全麻药被认为是通过直接与膜蛋白相互作用而作用于中枢神经系统的。由于离子通道是神经系统电兴奋性的本质，它们被认为是全麻药特别相关的靶点。这一设想的中心假设是吸入的全身麻醉药与离散的疏水腔相互作用，并通过变构偶联与涉及电压门控离子通道门控机制的效应部位发挥其生理作用。这项建议研究了NaChBac，一种哺乳动物电压门控钠(NAV)通道的细菌同系物，以表征吸入麻醉剂与电压门控钠通道的相互作用。本项目的目的是：1)研究S4-S5连接子和S6片段在电压门控钠通道吸入麻醉作用中的作用；2)研究电压门控钠通道吸入麻醉作用的结构基础。为了实现这些目标，将结合诱变、膜片钳电生理学、蛋白质生物化学、麻醉剂光标记和分子动力学模拟。这项工作将为哺乳动物NAV通道的类似研究提供一个垫脚石，哺乳动物NAV通道也受到相关剂量的吸入麻醉剂的调节，并为麻醉对NAV通道影响的机制研究打开大门。

Despite the ubiquitous use of general anesthetics, the molecular basis of general anesthesia has yet to be elucidated. The long-term goal of this study is to shed light on the molecular basis of general anesthetic action, which may open novel opportunities to design safer general anesthetics. General anesthetics are thought to act on the central nervous system by directly interacting with membrane proteins. Since ion channels are the essence of electrical excitability in the nervous system, they are considered particularly relevant targets of general anesthetics. The central hypothesis of this proposal is that inhaled general anesthetics interact with discrete hydrophobic cavities and exert their physiological effects through allosteric coupling with an effector site involving the gating machinery of voltage-gated ion channels. This proposal investigates NaChBac, a bacterial homolog of mammalian voltage-gated sodium (Nav) channels, to characterize inhaled anesthetic interactions with voltage gated sodium channels. The aims of this project are 1) to investigate the contributions of the S4-S5 linker and the S6 segment to inhaled anesthetic action in a voltage-gated sodium, channel, and 2) to investigate the structural basis of inhaled anesthetic action in a voltage-gated sodium channel. To pursue these aims a combination of mutagenesis, patch-clamp electrophysiology, protein biochemistry, anesthetic photolabeling and molecular dynamics simulations will be used. This work will provide a stepping-stone to similar investigations of mammalian Nav channels, which are also modulated by relevant doses of inhaled anesthetics and open the door to mechanistic studies of anesthetic effects on Nav channels.