THE ROLE OF EPSILON SUBUNIT IN GABAA RECEPTOR FUNCTION

描述：(申请人摘要) γ-氨基丁酸A型(GABAA)受体是主要的抑制物 大脑中的神经递质受体。全麻药对GABA的调节作用 受体通过一个未知的位置，人们普遍认为这是他们的 作用机制。这一理论已经不可能通过一个 麻醉剂结合部位缺乏拮抗剂。 GABAA受体每个由5个亚基组成，有15个已知变种 在哺乳动物中的这些多肽，提供了许多受体的潜力 子类型。不同的亚基组合可以形成不同的受体 特性，以及大脑中不同亚基的分布 提供了GABAA受体对不同种类的 治疗剂。GABAA受体对麻醉药的敏感性为 认为在发现新的亚基之前缺乏亚基的特异性 多肽(E)。E亚基在大脑中有独特的分布， 可以赋予表达它的神经元新的性质。的确， 当亚基与其他亚基结合形成细胞内的重组受体时 这些GABAA受体对麻醉剂的调节具有抵抗力。 E亚基与伽马亚基大部分序列相同，尽管 这两种多肽赋予GABAA受体的特性相当 截然不同。最值得注意的是，伽马亚基支持麻醉剂和苯二氮卓类药物 GABAA受体的调节，而e亚基不调节。 这个项目试图确定e亚基在控制GABAA中的作用。 受体功能。亚基将用来定义氨基酸基序 参与麻醉药对GABAA受体功能的调节。一位少校 该项目的目标是生产一种亚基，可以在未来的研究中 被引入转基因小鼠将在功能上拮抗麻醉剂 对GABAA受体的调节导致其他基因的最小可能变化 GABAA受体特性。具体目标1将决定e亚基是否 取代GABAA受体上的伽马亚单位。在Aim 2中嵌合e/Gamma2 构造将被用来探索结构和 由这些亚单位赋予的属性，特别强调识别 麻醉部位。《特定目标3》将检查全身麻醉药 使用类似的机制来调节其他离子亲电受体的功能 与GABAA受体相关。将特别强调5-HT3 受体。这种受体是相当有兴趣的，因为它被认为是 几种止吐剂的作用部位。人类同聚体和异构体 5-HT3受体受静脉麻醉剂异丙酚的调节 据报道具有止吐特性。

DESCRIPTION: (Applicant's Abstract) The gamma-aminobutyric type A (GABAA) receptor is the major inhibitory neurotransmitter receptor in the brain. General anesthetics modulate GABAA receptors through an unknown site and it is widely believed that this is their mechanism of action. This theory has been impossible to test by virtue of a lack of antagonists to anesthetic binding sites. GABAA receptors each consist of five subunits and there are 15 known varieties of these polypeptides in mammals, providing the potential for numerous receptor subtypes. Different subunit combinations can form receptors with distinct properties, and heterogeneous subunit distribution throughout the brain provides regional differences in the sensitivity of GABAA receptors to various therapeutic agents. The sensitivity of GABAA receptors to anesthetics was thought to lack subunit specificity until the identification of a new polypeptide (e). The e subunit has a distinctive distribution in the brain and may confer novel properties to the neurons in which it is expressed. Indeed, when the subunit is combined with others to form recombinant receptors in cell lines, these GABAA receptors exhibit a resistance to modulation by anesthetics. The e subunit shares most sequence identity with the gamma subunit, although the properties conferred to GABAA receptors by these two polypeptides are quite distinct. Most notably the gamma subunit supports anesthetic and benzodiazepine modulation of GABAA receptors while the e subunit does not. This project seeks to determine the role of the e subunit in controlling GABAA receptor function. The subunit will be used to define the amino acid motifs involved in the regulation of GABAA receptor function by anesthetics. A major goal of the project is to produce a subunit that can in future studies be introduced into transgenic mice which will functionally antagonize anesthetic regulation of GABAA receptors causing the minimum possible change in other GABAA receptor properties. Specific aim 1 will determine whether the e subunit displaces the gamma subunit from GABAA receptors. In Aim 2 chimeric e/gamma2 constructs will be used to probe the relationship between structure and the properties conferred by these subunits, with particular emphasis on identifying the anesthetic site. Specific aim 3 will examine whether general anesthetics use similar mechanisms to regulate the function of other ionotropic receptors related to the GABAA receptor. Particular emphasis will be placed on the 5-HT3 receptor. This receptor is of considerable interest as it is thought to be the site of action of several anti-emetic agents. Human homomeric and heteromeric 5-HT3 receptors are modulated by the intravenous anesthetic propofol which is reported to have anti-emetic properties.