Genes Underlying the Response to Inhaled Anesthetics

描述(由申请人提供)： 尽管挥发性麻醉剂用于外科手术已有150多年的历史，但其作用机制仍是个谜。这项研究计划旨在利用小鼠遗传模型来确定典型的挥发性麻醉药的作用机制。该提案详细介绍了一种以前没有应用于挥发性麻醉剂作用机制研究的方法。有两种方法确定了小鼠7号染色体上影响挥发性麻醉剂反应的区域：1)计算方法，将13个近交系小鼠对挥发性麻醉剂的表型反应与这些品系之间的单核苷酸多态(SNPs)模式相关联；2)分析来自2个具有不同麻醉剂(异氟烷)反应的亲本品系的回交后代。8个编码离子通道的候选基因在脊髓中表达，脊髓是挥发性麻醉剂诱导的不动的神经底物，在小鼠7号染色体上实验和计算确定的区域内被确定。这个建议有三个特定的目标。第一个目的是确定7号染色体上识别区域内的8个候选离子通道的特征。从两个对麻醉剂表现出高和低反应的小鼠品系中分离出的离子通道将在体外通过对表达通道的电生理实验来评估定性差异，并通过评估体内脊髓中的RNA表达来评估定量差异。目标是确定在分子水平上显示菌株差异的离子通道，这似乎可以解释菌株之间麻醉反应的差异。第二个目的是确定包含影响麻醉剂效力的基因的其他基因组区间。由于对挥发性麻醉药的反应不是以简单的孟德尔方式遗传的，除了7号染色体上确定的区域外，其他基因组间隔肯定会影响这种反应。高和低麻醉反应菌株的回交后代将被产生，并使用基于SNP的基因组扫描进行评估，以确定这些区域。第三个目的是培育同基因小鼠，在小鼠中，从对麻醉剂高反应的小鼠身上识别出的7号染色体片段被转移到低反应品系的遗传背景上，以便定量评估该区域(因此该区域的基因)对麻醉效力的影响。

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.