IN VITRO MODELS FOR ETHANOL EFFECTS ON RECEPTORS-MEDIATED PROCESSES

我们工作的一个主要重点是评估急性和 酒精对中枢神经系统的慢性影响。 然而，大脑 表示细胞类型的异质集合，并且 乙醇的直接和间接影响的区别， 难 体外细胞培养系统可用于监测 具体的，直接影响乙醇，比较和对比 在脑、组织和体内获得结果。 使用 小脑颗粒细胞的原代培养，我们发现乙醇， 在低浓度下，抑制谷氨酸（作用于红藻氨酸或 NMDA受体）刺激的环GMP产生。 环GMP 心房钠尿肽（ANP）刺激产生的量多， 对乙醇的抑制不太敏感。 结果表明 乙醇改变了谷氨酸受体-效应器的结合。 谷氨酸刺激可溶性鸟苷酸环化酶在钙- 依赖方式和初步研究结果表明，乙醇 改变谷氨酸依赖的钙流。 这些结果表明 关于乙醇的生物效应和相互作用的新假说 乙醇与NMDA偶联的钙通道也可能有助于 酒精耐受性和依赖性的发展。 在PC 12细胞中， 我们发现，虽然乙醇刺激腺苷酸环化酶（AC）， 在细胞膜中的活性，如在大脑中，乙醇抑制激动剂- 在完整PC 12一个亚克隆中刺激的环AMP积累 细胞 在第二个亚克隆中，乙醇通常增加环AMP 程度. 在第一个细胞中环AMP产生的抑制 亚克隆不依赖于Gi或蛋白激酶C活性。 的 结果表明，乙醇对环磷酸腺苷的影响 积累取决于交流调节的特性， 不同的细胞类型，因此外推到其他系统必须 谨慎 然而，细胞培养的使用允许 调查，可以加强我们对网站的了解， 乙醇的作用机制和生物化学的变化 可能与体内乙醇耐受性相关的系统， 身体依赖。

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. Using a primary culture of cerebellar granule cells, we found that ethanol, at low concentrations, inhibited glutamate (acting at kainate or NMDA receptors)-stimulated cyclic GMP production. Cyclic GMP production stimulated by atrial natriuretic peptide (ANP) was much less sensitive to ,inhibition by ethanol. The results suggested that glutamate receptor-effector coupling is altered by ethanol. Glutamate stimulates soluble guanylate cyclase in a calcium- dependent manner and preliminary findings indicate that ethanol alters glutamate-dependent calcium flux. These results suggest a new hypothesis for ethanol's depressant effects, and interaction of ethanol with NMDA-coupled calcium channels may also contribute to development of ethanol tolerance and dependence. In PC12 cells, we found that although ethanol stimulated adenylate cyclase (AC) activity in cell membranes, as in brain, ethanol inhibited agonist- stimulated cyclic AMP accumulation in one subclone of intact PC12 cells. In a second subclone ethanol often increased cyclic AMP levels. The inhibition of cyclic AMP production in the first subclone did not depend on Gi or on protein kinase C activity. The results demonstrate that the effect of ethanol on cyclic AMP accumulation depends on the characteristics of AC regulation in various cell types, so that extrapolations to other systems must be cautious. Nevertheless, the use of cell cultures allows investigations that can enhance our understanding of the sites and mechanisms of action of ethanol and of changes in biochemical systems that may, in vivo, be associated with ethanol tolerance and physical dependence.