Benzodiazepine Modulation of GABAa Receptor Kinetics

描述(申请人提供)：苯二氮卓类药物(BDZ)具有抗焦虑作用 以及变构在中枢神经系统(CNS)中的抗癫痫作用 GABAA受体氯电流的调制(IGABA)。因为广泛存在的 这些药物的临床应用，理解BDZ的作用机制(S) 改变离子通道功能是一个重要的药理研究课题。要确定 BDZ调控动力学跃迁的结构决定因素 通道激活，首先必须确定BDZ对已识别的、 野生型GABAA受体。这将通过快速药物应用来实现 技术和单通道录制，以测试哪些显微镜 A1 B2G2受体上的动力学速率常数受BDZ的调节而改变。我们 将利用GABA结合位点、孔区和 细胞外环梳理BDZ对 IGABA的结合/解绑和门控/脱敏。我们还将利用 系链串联亚基，在功能上分离每个 这两个GABA结合位点与这些过程有关。这篇文章中概述的研究 应用将有助于建立 GABAA受体的主要中枢神经系统变异体的临床相关药物和辅助 在建立关于结构-功能关系的可检验假说时 在这个和其他配基门控离子通道中。

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.