Regulation of Ethanol Effects on Synaptic Transmission

描述(申请人提供)：该项目的主要目标是了解酒精中毒和依赖的神经元、细胞和突触机制，使用脑片和活体微透析的细胞内和膜片钳记录。一个中心假设是，突触的适应性变化会导致酒精依赖。我们还假设GABA能系统中的神经适应在酒精增强作用中发挥重要作用。我们过去的研究集中在杏仁中央核(CEA)的神经元上，因为行为研究表明，杏仁核及其与终纹NAcc和床核的联系，被称为延长的杏仁核，在酒精的急性强化效应和对酒精戒断的焦虑反应中发挥着重要作用。我们计划的研究基于以下基本原理：1)急性乙醇通过激活CRF1受体显著增强CEA的GABA能神经传递。我们提出的第一个直接证据表明，乙醇诱导的GABA能反应的增加部分是由于GABA释放的增加。2)我们的初步数据还表明，慢性乙醇处理(GET)显著提高了CEA的基础GABA能张力。3)尽管基础GABA释放显著增加，GET大鼠CEA对急性乙醇诱导的GABA释放缺乏耐受性。4)我们的初步证据表明，GET后CRF系统和GABAB受体在调节突触效能方面发生了神经适应性变化。因此，在这一应用中，我们建议使用多学科方法来研究乙醇与GABA能传递相互作用的细胞和分子基础。特异性AIMS 1和2将在体外和体内测试突触前CRF受体、膜钙通道及其转导机制与GABA释放机制在急性(AIM 1)和慢性(AIM 2)乙醇对CEA神经元影响中的可能参与。了解乙醇增强急性和慢性乙醇诱导的GABA IPSP的突触前机制是酒精研究的新挑战，也是开发治疗酒精中毒的化合物的可能靶点。

DESCRIPTION (provided by applicant): The primary objective of this project is to understand the neuronal, cellular and synaptic mechanisms underlying alcohol intoxication and dependence, using intracellular and patch-clamp recording in brain slices and in vivo microdialysis. A central hypothesis is that adaptive changes in synapses cause alcohol dependence. We also hypothesize that neuroadaptations in the GABAergic system play a major role in alcohol reinforcing actions. Our past research has centered on neurons of the central nucleus of the amygdala (CeA), because behavioral studies suggest that the amygdala, and its connections to the NAcc and bed nucleus of the stria terminalis, termed the 'extended amygdala,' play a major role in the acute reinforcing effects of ethanol and in the anxiogenic response to ethanol withdrawal. Our planned studies are based on the following rationale: 1) Acute ethanol markedly enhances GABAergic neurotransmission in CeA through the activation of CRF1 receptors. We present the first direct evidence that this ethanol-induced increase in GABAergic response is in part due to increased GABA release. 2) Our preliminary data also indicate that chronic ethanol treatment (GET) greatly enhances baseline GABAergic tone in the CeA. 3) Despite this large increase in basal GABA release, there is a lack of tolerance to acute ethanol-induced GABA release in CeA of GET rats. 4) Our preliminary evidence of neuroadaptive changes in the CRF system and in GABAB receptors in modulating synaptic efficacy following GET. Therefore in this application we propose to study the cellular and molecular basis of ethanol interactions with GABAergic transmission using a multidisciplinary approach. Specific Aims 1 and 2 will test, in vitro and in vivo, the possible involvement of presynaptic CRF receptors, membrane Ca++ channel and their transduction mechanisms coupled to the regulation of GABA release machinery in the effect of acute (Aim 1) and chronic (Aim 2) ethanol in CeA neurons. Understanding the specific presynaptic mechanisms underlying ethanol enhancement of GABA IPSPs induced by both acute and chronic ethanol represents a new challenge for alcohol research and a possible target for the development of therapeutic compounds for the treatment of alcoholism.