NEUROTOXIN INTERACTIONS WITH RECOMBINANT GABAA RECEPTORS

这项研究提案的总体目标是确定机制 GABAA受体特异性杀虫剂和相关神经毒素的作用。 杀虫剂发挥其毒性作用的显著机制 似乎是通过与电压门控或配基门控的相互作用 离子通道。有证据表明，许多杀虫剂的效果是 由于与昆虫的GABA受体相互作用。昆虫受体 与脊椎动物的GABAA受体相对同源，并且 因此，其中许多杀虫剂对脊椎动物也是有毒的。 然而，这些杀虫剂和其他杀虫剂 神经毒素阻断GABAA受体的活性尚未被 下定决心。此外，试图调查这一点的研究 这个问题还没有使用人类衍生的受体进行。因此， 膜片钳技术将被用来确定其机制。 重组人和大鼠GABAA受体表达的神经毒性作用 在人类胚胎肾脏细胞中。这项研究的具体目的 建议是：i)检验神经毒素发挥其作用的假设 对重组GABAA受体的抑制作用 单通道开放概率；2)检验假设 GABA增强神经毒素与其结合的结合率 在重组GAAA受体上的(S)位点；3)检验假设 GABA受体相关神经毒素的动力学相互作用受到影响 通过重组GABAA受体的亚基配置；4)检测 重组GABAA的磷酸化状态假说 受体调节神经毒素的作用。这些研究的结果 研究将加强我们对神经毒剂如何发挥作用的理解 它们对哺乳动物中枢神经系统的毒性作用。这 信息应有助于开发符合以下条件的杀虫剂 对人类和其他脊椎动物的毒性较小。这些研究的结果 还将提供有关配体受体调节的一般信息 GABAA受体的相互作用；这一知识可能与 整个配基门控离子通道超家族。

The overall goal of this research proposal is to determine the mechanism of action of GABAA receptor-specific insecticides and related neurotoxins. A prominent mechanism by which insecticides exert their toxic effects appears to be through an interaction with voltage-gated or ligand-gated ion channels. Evidence suggests that the effects of many insecticides are due to an interaction with the insect GABA receptor. The insect receptor is relatively homologous with the vertebrate GABAA receptor, and consequently many of these insecticides are also toxic to vertebrates. However, the mechanism through which these insecticides and other neurotoxins block the activity of the GABAA receptor has not been determined. Moreover, studies that have attempted to investigate this question have not been conducted using human-derived receptors. Thus, the patch clamp technique will be used to determine the mechanism of neurotoxic action on recombinant human and rat GABAA receptors expressed in human embryonic kidney cells. The specific aims of this research proposal are to: i) test the hypothesis that neurotoxins exert their inhibitory effects on the recombinant GABAA receptor by decreasing' single-channel open probability; 2) test the hypothesis that the presence of GABA enhances the association rate of the neurotoxins to their binding site(s) on the recombinant GABAA receptor; 3) test the hypothesis that the kinetic interactions of GABA receptor-related neurotoxins are influenced by subunit configuration of the recombinant GABAA receptor; and 4) test the hypothesis that phosphorylation state of the recombinant GABAA receptor modulates the effects of the neurotoxins. The results of these studies will enhance our understanding of how neurotoxic agents exert their toxic effects on the mammalian central nervous system. This information should be useful in the development of insecticides that are less toxic to humans and other vertebrates. Results from these studies will also provide general information about modulation of ligand receptor interactions for the GABAA receptor; this knowledge may be relevant to the whole superfamily of ligand-gated ion channels.