INIA: Chimeric Analysis of Alcohol & Stress Interactions

描述(由申请人提供)： 酒精中毒和与酒精相关的表型有很强的遗传成分。 许多候选基因被认为在决定 这些表型包括NMDA、5-羟色胺和GABA系统。通常， 一种证明这些候选分子中哪些实际上负责的方法 因为表型是通过使用基因敲除小鼠来实现的。在某些情况下， 解决这个问题的能力是复杂的，因为突变是 胚胎或新生儿致死，使人无法确定 基因在大多数行为表型中，特别是与酒精相关的行为中。 消除问题的一种方法是使用嵌合小鼠。 嵌合小鼠是由突变体和野生鼠混合而成的--在许多情况下， 野生型细胞的存在能够消除允许 对动物的分析。NMDA受体已被假设为介导 与酒精有关的多种影响，包括增加酒精摄入量和 戒断效应的严重程度。此外，NMDA受体已被证明 在应对压力的过程中发挥重要作用。NMDA受体复合体由 目前还不清楚哪些亚基对 这些影响。被假设为重要的两个亚单位是 NRI和NR2B亚基。这两个亚基的敲除都处于萌芽状态。 致命的，因此，每个受体的作用的最终解决方案是 未知。为了确定这些受体的作用，两个不同的嵌合体 将进行以下组合：野生型和野生型 嵌合体小鼠。成年嵌合体小鼠将在两瓶选择上进行测试 酒精消耗测试和脚部电击压力测试的响应 在高架加号迷宫中进行评估。随后，每个嵌合体的大脑 将对老鼠进行组织学分析，以确定1)是否存在基因 剂量效应，即如果嵌合体小鼠的行为更加异常 突变细胞的比例更高，以及2)如果有更重要的 某些脑区的敲除细胞与其他脑区的敲除细胞。这些数据将提供 对NR1和NR2B基因在这些表型中的作用的洞察。

DESCRIPTION (provided by applicant): Alcoholism and alcohol-related phenotypes have a strong genetic component. Numerous candidate genes have been hypothesized to be critical in determining these phenotypes including NMDA, serotonin and GABA systems. Typically, the way to demonstrate which of these candidate molecules are in fact responsible for the phenotype is through the use of knock-out mice. In some instances, the ability to address this issue is complicated by the fact that the mutation is embryonic or neonatal lethal making it impossible to ascertain the role of the gene in most behavioral phenotypes, particularly ethanol-related behaviors. One method of eliminating problem is through the use of chimeric mice. Chimeric mice are made by mixing mutant and wild-tax e many instances, the presence of wild-type cells is able to eliminate the lethality allowing for the analysis of animals. NMDA receptors have been hypothesized to mediate multiple alcohol-related effects including increased alcohol consumption and severity of withdrawal effects. Additionally, NMDA receptors have been shown to be important in responses to stress. The NMDA receptor complex is made up of multiple subunits and it is unclear which of the subunits are critical for these effects. Two subunits that have been hypothesized to be important are the NRI and NR2B subunits. Knock-outs of both of these subunits are embryonic lethal and thus, the definitive resolution of the role of each receptor is unknown. To determine the role of these receptors, two different chimeric combinations will be make: NRI-/-<-> wild-type and NR2B-/-<-> wild-type chimeric mice. Adult chimeric mice will be tested on both a two-bottle choice test of ethanol consumption and in a response to stress test using foot shock evaluated in an elevated plus maze. Subsequently, the brains of each chimeric mouse will be analyzed histologically to determine 1) if there is a gene dosage effect i.e. if the behavior is more abnormal in chimeric mice with a higher percentage of mutant cells, and 2) if there is a greater importance of knock-out cells in some brain regions versus others. This data will provide insights into the role of the NR1 and NR2B genes in these phenotypes.