GABA RECEPTOR COMPLEX IN ALCOHOL DEPENDENCE

酒精依赖性的 GABA 受体复合体

• 批准号: 3111502
• 负责人: RICHARD W OLSEN
• 金额: $ 17.58万
• 依托单位: UNIVERSITY OF CALIFORNIA LOS ANGELES
• 依托单位国家: 美国
• 财政年份: 1993
• 资助国家: 美国
• 起止时间: 1993-08-01 至 1996-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/3111502
• 关键词: GABA receptor; Xenopus oocyte; affinity labeling; alcoholism /alcohol abuse; alcoholism /alcohol abuse chemotherapy; anesthetics; autoradiography; benzodiazepines; drug metabolism; drug tolerance; drug withdrawal; electrophysiology; electrostimulus; ethanol; generalized seizures; kindling; laboratory rat; memory; neurochemistry; phosphorylation; picrotoxin; polymerase chain reaction; radiotracer; scintillation counter; second messengers; western blottings

The objectives of this study are to determine whether persistent alterations in the GABA receptor complex can provide a molecular explanation for the development of physical dependence on ethanol in an animal model of alcoholism. Chronic intermittent administration of ethanol (CIE) to rats has many features resembling human alcohol abuse behavior, including relevance to the long-lasting susceptibility to readdiction. The numerous episodes of ethanol induced depression of the CNS and the following rebound hyperexcitability have been shown to exert a kindling-like effect during the period of hyperexcitability. When ethanol is administered to rats under a regimen designed to promote kindling effects, the development of ethanol dependence is associated with a decreased seizure threshold to the convulsant pentylenetetrazol (PTZ), known to interact with the GABAA receptor-chloride ion channel complex. This hyperexcitability (kindling) to PTZ lasts for at least 40 days after cessation of ethanol. Neurochemical studies have been directed towards determining whether ethanol dependence and changes of seizure threshold can be correlated with alterations in the molecular properties of the GABAA receptor complex. PTZ receptors, assayed by the binding of [35S]TBPS, are increased in ethanol dependence, and benzodiazepine- insensitive binding sites for the alcohol antidote drug [3H]Rol5-4513 are decreased, while binding of other radioligands and allosteric modulators for the GABAA receptor complex such as neurosteroids are not changed. Polymerase chain reaction (PCR) measurements show that the ratio of receptor subunit mRNAs is altered, suggesting the production of novel receptor oligomeric subtypes. The subunit composition of these novel receptors will be determined by protein chemistry including~photoaffinity labeling and Western blotting with subunit-specific antibodies; their properties will be studied by electrophysiology on Xenopus oocytes expressing recombinant receptors of defined subunit composition. Further comparisons of alcohol-dependent and naive rats will study function of GABAA receptors using 36Cl- flux, radioligand binding/ autoradiography, and potential long-lasting protein modification by phosphorylation.

这项研究的目标是确定持续的 GABA受体复合体的改变可以提供一个分子 对老年人身体对酒精依赖发展的解释 酒精中毒的动物模型。慢性间歇性给药 乙醇对大鼠有许多类似于人类酒精滥用的特征 行为，包括与长期易感的相关性 再读一遍。酒精引起的抑郁症的多次发作 中枢神经系统和以下反弹的超兴奋性已被证明发挥作用 在过度兴奋期间的一种点燃效应。什么时候 给老鼠注射乙醇的方案是为了促进 点燃效应，酒精依赖的发展与 惊厥剂戊四唑(PTZ)的惊厥阈值降低， 已知与GABAA受体-氯离子通道复合体相互作用。 这种对PTZ的过度兴奋(点燃)在之后至少持续40天 停止使用乙醇。神经化学研究的方向是 测定酒精依赖与癫痫发作阈值的变化 可能与细胞分子性质的改变有关 GABAA受体复合体。PTZ受体的结合测定 [35S]，在酒精依赖中增加，而苯二氮类药物- 酒精解毒剂药物[~3H]Rol5-4513的不敏感结合部位为 减少，同时结合其他放射性配体和变构调节剂 对于GABAA受体复合体等神经类固醇是不变的。 聚合酶链式反应(PCR)检测显示， 受体亚单位mRNAs发生改变，提示新的 受体寡聚体亚型。这些小说的亚单位构成 受体将由蛋白质化学确定，包括光亲和力 亚基特异性抗体的标记和免疫印迹 非洲爪哇卵母细胞的电生理学特性研究 表达确定亚基组成的重组受体。进一步 酒精依赖大鼠和幼稚大鼠的比较将研究 用~(36)Cl-通量、放射性配基结合/放射自显影， 以及潜在的通过磷酸化进行的持久的蛋白质修饰。