IN VITRO MODELS FOR ETHANOL EFFECTS ON RECEPTOR-MEDIATED PROCESSES

我们工作的一个主要重点是评估急性和慢性 乙醇对中枢神经系统的影响。然而，大脑代表着一种 不同类型的细胞集合，并区分直接和 乙醇的间接影响可能很难实现。体外细胞培养系统 可用于监测乙醇的特定、直接影响，以供比较 并与在脑组织和活体内获得的结果进行对比。当前 乙醇对人鼻咽癌原代培养细胞NMDA受体影响的研究 小脑颗粒细胞现在在AA00706项目中被描述。此外, NCB20体细胞杂交种5-羟色胺受体的研究 正在进行中，并基于1)乙醇增强 5-羟色胺-3受体激动剂在电生理中的作用 NCB20细胞的研究，以及2)5-羟色胺-3受体拮抗剂阻断 乙醇的区别刺激特性(见项目AA00707)。至 确定乙醇是否直接影响配体与 与这些受体结合的5HT-3受体、拮抗剂和激动剂是 通过过滤器结合技术进行评估。拮抗剂~3H-GR65630结合 NCB20膜上的单一位点和激动剂(5-羟色胺，2-Me-5羟色胺)置换 乙醇(12.5-100 mm)无 对激动剂或拮抗剂结合有显著影响，并可能 影响受体-效应器耦合过程。行为研究表明 乙醇在5-羟色胺-3受体上的作用在调节 酒精的主观影响(如强化、醉酒)和 对培养细胞的研究可能提出了一种生化机制 这些在体内的反应。

A major focus of our work involves an evaluation of the acute and chronic effects of ethanol in the CNS. However, the brain represents a heterogeneous collection of cell types, and distinction of direct and indirect effects of ethanol can be difficult. In vitro cell culture systems can be used to monitor specific, direct effects of ethanol, for comparison and contrast with results obtained in brain tissue and in vivo. Current studies of the effect of ethanol on NMDA receptors in primary cultures of cerebellar granule cells are now described in project AA00706. In addition, investigations of serotonin (5HT-3) receptors in NCB20 somatic cell hybrids are being performed, and are based on the findings that 1) ethanol enhances the action of agonists at the 5HT-3 receptor in electrophysiological studies of NCB20 cells, and 2) 5HT-3 receptor antagonists block the discriminative stimulus properties of ethanol (see Project AA00707). To determine whether ethanol directly affects the interaction of ligands with the 5HT-3 receptor, antagonist and agonist binding to these receptors were assessed by filter binding techniques. The antagonist, 3H-GR65630, bound to a single site on NCB20 membranes, and agonist (5HT, 2-Me-5HT) displacement curves were best fit by a one-site model.Ethanol (12.5 - 100 mM) had no significant effect on either agonist or antagonist binding, and may instead affect receptor-effector coupling processes. The behavioral studies suggest that the action of ethanol at the 5HT-3 receptor is important in mediating subjective effects of ethanol (e.g., reinforcement, intoxication) and studies in cultured cells may suggest a biochemical mechanism underlying these in vivo responses.