ETHANOL DISRUPTION OF CENTRAL MUSCARINIC TRANSMISSION

这项拟议的研究的目的是了解乙醇是如何 影响M胆碱受体功能的实验研究 大脑中的复合体。我们已经证明了乙醇1) 改变与受体的配基结合，2)破坏受体 偶联到依赖鸟嘌呤核苷酸的转导蛋白(G 蛋白质)。后一种效应代表了一种新的机制 突触传递中断。需要检验的假设 乙醇是否与M-G蛋白复合体相互作用 大脑，从而影响1)与受体的配体结合，2) 甘氨酸对受体结合的核苷酸调节，3)受体 突触后生化事件的调节，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GTPase活性。 因此，拟议研究的具体目标是 确定乙醇和其他短卡辛醇对 M受体及其相关的G蛋白 在老鼠脑中。有待研究的受体过程有：1)配体 结合，包括拮抗剂结合部位密度、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 鸟嘌呤核苷酸调节激动剂的偶联作用 结合，3)M受体介导的腺苷抑制 环化酶活性与磷脂酰肌醇分解的刺激 在脑膜中，作为功能性毒扁豆碱的指示 传递，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鼠强的了解 大脑中的受体组织和功能，并提供洞察力 乙醇破坏突触的分子基础 变速箱。

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.