Genes Underlying the Response to Inhaled Anesthetics

描述（由申请人提供）： 虽然挥发性麻醉剂已用于外科手术超过150年，其作用机制仍然是一个谜。本研究计划旨在使用小鼠遗传模型确定原型挥发性麻醉剂的作用机制。该提案详细介绍了一种以前未应用于挥发性麻醉剂作用机制研究的方法。两种方法鉴定了小鼠7号染色体上影响挥发性麻醉剂反应的区域：1）将13个近交系小鼠品系中对挥发性麻醉剂的表型反应与这些品系中的单核苷酸多态性（SNP）模式相关联的计算方法;和2）分析来自具有不同麻醉剂（异氟烷）反应的2个亲本品系的回交后代。在小鼠7号染色体上的实验和计算鉴定区域内鉴定了编码脊髓中表达的离子通道的8个候选基因，脊髓是挥发性麻醉剂诱导的不动性的神经底物。这项建议有三个具体目标。第一个目标是表征7号染色体上所识别区域内的8个候选离子通道。从对麻醉剂表现出高和低反应的两种小鼠品系中分离的离子通道将在体外表达通道的电生理学实验中评价定性差异，并通过评价体内脊髓中的RNA表达来评价定量差异。目的是确定在分子水平上显示菌株差异的离子通道，这些差异可解释菌株之间麻醉反应的差异。第二个目的是确定其他基因组区间，包含影响麻醉剂效力的基因。因为对挥发性麻醉剂的反应不是以简单的孟德尔方式遗传的，除了在7号染色体上鉴定的区域之外，其他基因组间隔必须影响这种反应。将使用基于SNP的基因组扫描生成和评价来自高和低麻醉反应菌株的回交后代，以鉴定这些区域。第三个目的是产生同源小鼠，其中将来自对麻醉剂具有高反应的小鼠的鉴定的7号染色体片段转移到低反应品系的遗传背景上，以定量评估该区域（以及该区域中的基因）对麻醉剂效力的影响。

DESCRIPTION (provided by applicant): Although volatile anesthetics have been used in surgical procedures for over 150 years, their mechanism of action remains an enigma. This research proposal aims to identify the mechanism of action of prototypic volatile anesthetics using a murine genetic model. The proposal details an approach not previously applied to investigations of mechanisms of volatile anesthetic action. Two methods identified a region on mouse chromosome 7 which influences volatile anesthetic response 1) a computational method correlating the phenotypic response to volatile anesthetics among 13 inbred mouse strains with the pattern of single nucleotide polymorphisms (SNPs) among these strains; and 2) analysis of backcross progeny derived from 2 parental strains with different anesthetic (isoflurane) responses. Eight candidate genes coding for ion channels expressed in the spinal cord, which is the neural substrate of volatile anesthetic-induced immobility, were identified within the experimentally and computationally identified region on mouse chromosome 7. This proposal has three specific aims. The first aim characterizes the 8 candidate ion channels within the identified region on chromosome 7. Ion channels isolated from two mouse strains exhibiting high and low responses to anesthetic agents will be evaluated for qualitative differences in electrophysiologic experiments on expressed channels in vitro, and for quantitative differences by evaluation of RNA expression in the spinal cord in vivo. The goal is to identify ion channels that display strain differences at a molecular level that plausibly account for the difference in anesthetic response between strains. The second aim identifies other genomic intervals that contain genes influencing anesthetic potency. Because response to volatile anesthetics is not inherited in simple Mendelian fashion, in addition to the region identified on chromosome 7, other genomic intervals must influence this response. Backcross progeny from high and low anesthetic response strains will be generated and evaluated using a SNP-based genome scan to identify these regions. The third aim produces congenic mice in which the identified chromosome 7 segment from mice with high responses to anesthetic is transferred onto the genetic background of the low responder strain, in order to quantitatively assess the effect of this region (and hence the genes in this region) on anesthetic potency.