Insecticide Action at the Local Anesthetic Receptor

局部麻醉受体的杀虫作用

• 批准号: 7179568
• 负责人: DAVID M SODERLUND
• 金额: $ 24.18万
• 依托单位: CORNELL UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2006
• 资助国家: 美国
• 起止时间: 2006-12-01 至 2011-11-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7179568
• 关键词: Alanine; Amino Acids; Analgesics; Anticonvulsants; Binding; Cells; Class; Condition; Elements; Exhibits; Funding; Insecta; Insecticides; Kinetics; Local Anesthetics; Maps; Membrane Potentials; Molecular; Molecular Structure; Mutate; Mutation; Neuroprotective Agents; Pharmaceutical Preparations; Pharmacology; Protein Isoforms; Rattus; Research; Rest; Role; Site; Site-Directed Mutagenesis; Sodium; Sodium Channel; Sodium Channel Binding; Structure; Testing; Therapeutic; Tissues; United States; Xenopus; Xenopus oocyte; indoxacarb; insight; neurotoxic; receptor; voltage; voltage clamp

DESCRIPTION (provided by applicant): 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.

描述（由申请人提供）：吡唑啉型杀虫剂（PTIS）是IndoxaCarb示例的一类新杀虫剂，这是美国在美国注册商业用途的类的第一大化合物。 PTI通过选择性地阻断去极化细胞中的钠通道，在昆虫中发挥神经毒性作用。 PTI还有选择性地阻断哺乳动物钠通道处的膜电位，从而促进慢速钠通道失活。在许多方面，这种作用与由多种治疗药物（例如，局部麻醉药，抗心律失常，抗惊厥药，神经保护剂和镇痛药）引起的状态依赖性钠通道阻滞相似，它们与钠通道的“局部麻醉受体”部位结合。结果，局部麻醉受体已间接牵涉到PTI作用部位。拟议的研究将通过与慢速灭活的钠通道的局部麻醉受体位点结合来检验PTIS阻断钠通道的假设。拟议的资金期间的具体实验目的是：（1）定义PTI在Xenopus卵母细胞中表达的克隆大鼠钠通道同工型和亚基组合的作用； （2）通过PTIS阐明电压依赖性钠通道阻滞的机理； （3）通过定点诱变来绘制PTI与钠通道结合的结构决定因素。克隆的钠通道同工型将在爪蟾卵母细胞中表达，PTI对表达通道的作用将使用在电压钳条件下的钠电流的电生理记录来评估。这些研究的结果将定义钠通道同工型对PTI的差异敏感性，通过这些化合物阐明了状态依赖性钠通道阻滞的机理，并确定了PTI与钠通道的分子决定因素。这项研究将为局部麻醉受体的结构及其在PTI的神经毒性作用中的作用提供新的见解。