Insecticide Action at the Local Anesthetic Receptor

局部麻醉受体的杀虫作用

基本信息

批准号：
7996052
负责人：
DAVID M SODERLUND
金额：
$ 23.3万
依托单位：
CORNELL UNIVERSITY
依托单位国家：
美国
项目类别：
财政年份：
2006
资助国家：
美国
起止时间：
2006-12-01 至 2012-11-30
项目状态：
已结题

项目摘要

Pyrazoline-type insecticides (PTIs) are a new class of insecticides exemplified by indoxacarb, the first compound of the class registered for commercial use in the United States. PTIs exert their neurotoxic effects in insects by selectively blocking sodium channels in depolarized cells. PTIs also selectively block mammalian sodium channels at membrane potentials that promote slow sodium channel inactivation. This effect is similar in many respects to the state-dependent sodium channel block caused by several classes of therapeutic drugs (e.g., local anesthetics, antiarrhythmics, anticonvulsants, neuroprotectants and analgesics) that bind to the "local anesthetic receptor" site of sodium channels. As a result, the local anesthetic receptor has been implicated indirectly as the site of PTI action. The proposed research will test the hypothesis that PTIs block sodium channels by binding to the local anesthetic receptor site of slow-inactivated sodium channels. Specific experimental aims for the proposed funding period are: (1) to define the actions of PTIs on cloned rat sodium channel isoforms and subunit combinations expressed in Xenopus oocytes; (2) to elucidate the mechanism of voltage-dependent sodium channel block by PTIs; and (3) to map the structural determinants of PTI binding to sodium channels by site-directed mutagenesis. Cloned sodium channel isoforms will be expressed in Xenopus oocytes and the actions of PTIs on expressed channels will be assessed using electrophysiological recordings of sodium currents under voltage-clamp conditions. Results of these studies will define the differential sensitivity of sodium channel isoforms to PTIs, elucidate the mechanism of state-dependent sodium channel block by these compounds, and identify the molecular determinants of PTI binding to sodium channels. This research will provide new insight into the structure of the local anesthetic receptor and its role in the neurotoxic actions of PTIs.

吡唑啉类杀虫剂（PTI）是一类新型杀虫剂，以茚虫威为代表，第一种杀虫剂。在美国注册用于商业用途的此类化合物。 PTI 发挥神经毒性通过选择性阻断去极化细胞中的钠通道来对昆虫产生影响。 PTI 还选择性地阻止哺乳动物钠通道的膜电位促进钠通道缓慢失活。这效果在许多方面与由几类药物引起的状态依赖性钠通道阻滞相似治疗药物（例如局部麻醉药、抗心律失常药、抗惊厥药、神经保护药和镇痛药）与钠通道的“局部麻醉受体”位点结合。结果，局麻药受体已被间接牵连为 PTI 行动场所。拟议的研究将检验以下假设： PTI 通过与缓慢失活的钠的局部麻醉受体位点结合来阻断钠通道渠道。拟议资助期的具体实验目标是：(1) 定义 PTI 的行动对非洲爪蟾卵母细胞中表达的克隆大鼠钠通道亚型和亚基组合的影响； (2) 至阐明 PTI 电压依赖性钠通道阻滞的机制； (3) 绘制结构图通过定点诱变 PTI 与钠通道结合的决定因素。克隆钠通道同工型将在非洲爪蟾卵母细胞中表达，PTI 对表达通道的作用将是使用电压钳条件下钠电流的电生理记录进行评估。结果这些研究将定义钠通道亚型对 PTI 的不同敏感性，阐明这些化合物的状态依赖性钠通道阻断机制，并确定了分子 PTI 与钠通道结合的决定因素。这项研究将为我们的结构提供新的见解局麻药受体及其在 PTI 神经毒性作用中的作用。