Benzodiazepine Modulation of GABAa Receptor Kinetics

性状（由申请方提供）：苯二氮卓类（BDZ）具有抗焦虑作用 和通过变构的中枢神经系统（CNS）中的抗癫痫作用 GABAA受体Cl-电流（IGABA）的调节。由于广泛的 这些药物的临床效用，了解BDZ 改变离子通道功能是一项重要的药理学研究。以识别 BDZ调节动力学转变的结构决定因素 通道激活，必须首先确定BDZ对识别的， 野生型GABAA受体。这将通过快速药物应用来实现 技术和单通道记录，以测试哪些显微镜 动力学速率常数被α 1 B2 g2受体中的调节性BDZ改变。我们 将利用GABA结合位点、孔区域和细胞膜中的突变， 细胞外环梳理除了BDZ的贡献， 结合/解结合和门控/脱敏。我们也会利用 系连的串联亚基在功能上分离每个亚基的贡献， 这两个GABA结合位点的作用。本文中概述的研究 应用将有助于建立有效的行动机制， 临床相关药物对GABAA受体的主要CNS变体的作用， 在建立关于结构-功能关系的可检验的假说时， 在这个和其他配体门控离子通道中。

DESCRIPTION (provided by applicant): Benzodiazepines (BDZs) exert anxiolytic and anti-epileptic effects in the central nervous system (CNS) by allosteric modulation of the GABAA receptor Cl- current (IGABA). Because of the widespread clinical utility of these drugs, understanding the mechanism(s) by which BDZs alter ion channel function is an important pharmacological inquiry. To identify the structural determinants underlying BDZ modulation of kinetic transitions of channel activation, one must first determine the effects of BDZs on identified, wild-type GABAA receptors. This will be approached using rapid drug application techniques and single-channel recordings to test which of the microscopic kinetic rate constants are altered by modulatory BDZs in a1 B2g2 receptors. We will make use of mutations in the GABA binding site, the pore region, and the extracellular loop to tease apart the contributions of BDZs to binding/unbinding and gating/desensitization of IGABA. We will also make use of tethered tandem subunits to functionally separate the contributions of each of the two GABA binding sites to these processes. The studies outlined in this application will help to establish the functional mechanisms of action for clinically relevant drugs on a major CNS variant of the GABAA receptor, and aid in establishing testable hypotheses regarding structure-function relationships in this and other ligand-gated ion channels.