ETHANOL DISRUPTION OF CENTRAL MUSCARINIC TRANSMISSION

这项研究的目的是了解乙醇是如何 影响毒蕈碱型乙酰胆碱受体的功能 大脑中的复合体。 我们已经证明，乙醇1） 改变配体与受体的结合和2）破坏受体 与鸟嘌呤核苷酸依赖性转导蛋白（G 蛋白质）。 后一种效应代表了一种新的机制， 破坏突触传递。 待检验的假设 乙醇与毒蕈碱-G蛋白复合物相互作用， 大脑，从而影响1）配体与受体的结合，2） 鸟嘌呤核苷酸调节受体结合，3）受体 调节突触后生化事件，4）鸟嘌呤 与受体相关G蛋白结合的核苷酸，和/或5） G蛋白的GT3活性。 因此，拟议研究的具体目标是 确定乙醇和其他短咖啡因醇对 毒蕈碱（和其他）受体及其相关G蛋白 在老鼠的大脑中。 待研究的受体过程是1）配体 结合，包括拮抗剂结合位点密度，亲和力， 动力学和热力学以及激动剂结合特性 （亚群分布和亲和力），2）受体-G蛋白 偶联，如通过激动剂的鸟嘌呤核苷酸调节所揭示的 结合，3）毒蕈碱受体介导的腺苷酸抑制 环化酶活性和刺激磷脂酰肌醇分解 在脑膜中，作为功能性毒蕈碱的指示 传输，和4）GTP酶和（345）GTP结合活性 从大鼠脑中分离的G蛋白种类，以评估 酒精-G蛋白直接相互作用的可能性。 这项研究将增加我们对毒蕈碱的了解 大脑中的受体组织和功能， 乙醇破坏突触的分子基础 传输

The aim of the proposed research is to understand how ethanol affects the function of muscarinic acetylcholine receptor complexes in the brain. We have demonstrated that ethanol 1) alters ligand binding to the receptor and 2) disrupts receptor coupling to guanine nucleotide-dependent transducer proteins (G proteins). The latter effect represents a novel mechanism for disruption of synaptic transmission. The hypotheses to be tested are that ethanol interacts with muscarinic-G protein complexes in the brain, thereby affecting 1) ligand binding to the receptor, 2) gaunine nucleotide regulation of receptor binding, 3) receptor regulation of postsynaptic biochemical events, 4) guanine nucleotide binding to receptor-associated G proteins, and/or 5) the GTPase activity of G proteins. Accordingly, the Specific Aims of the proposed research are to determine the effects of ethanol and other short cahin alcohols on muscarinic (and other) receptors and their associated G proteins in rat brain. Receptor processes to be studied are 1) ligand binding, including antagonist binding site density, affinity, kinetics and thermodynamics, and agonist binding propetties (subpopulation distribution and affinities), 2) receptor-G protein coupling, as revealed by guanine nucleotide regulation of agonist binding, 3) muscarinic receptor-mediated inhibition of adenylate cyclase activity and stimulation of phosphatidylinositol breakdown in brain membranes, as an indication functional muscarinic transmission, and 4) the GTPase and (345)GTP binding activities of G protein species isolated from rat brain, to evaluate the possibility of direct alcohol-G protein interactions. This research will increase our understanding of muscarinic receptor organization and function in the brain and provide insight into the molecular bases for ethanol disruption of synaptic transmission.