Regulation of Ethanol Effects on Synaptic Transmission

描述（由申请人提供）：本项目的主要目的是通过细胞内和膜片钳记录脑切片和体内微透析，了解酒精中毒和依赖的神经元、细胞和突触机制。一个中心假设是突触的适应性变化导致了酒精依赖。我们还假设gaba能系统中的神经适应在酒精强化行为中起主要作用。我们过去的研究集中在杏仁核中央核（CeA）的神经元上，因为行为学研究表明，杏仁核及其与终纹的NAcc和床核的连接，被称为“延伸的杏仁核”，在乙醇的急性强化效应和对乙醇戒断的焦虑反应中起着重要作用。我们计划的研究基于以下原理：1)急性乙醇通过激活CRF1受体显著增强CeA中gaba能神经传递。我们提出了第一个直接证据，证明乙醇诱导的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，慢性乙醇治疗（GET）大大提高了CeA的基线gaba能张力。3)尽管基础GABA释放量大幅增加，但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，在GET后，CRF系统和GABAB受体的神经适应性变化调节突触效能。因此，在本应用中，我们建议采用多学科方法研究乙醇与gaba能传输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ca++通道及其与GABA释放机制耦合的转导机制在急性（Aim 1）和慢性（Aim 2）乙醇对CeA神经元的影响中的可能参与。了解急性和慢性乙醇诱导GABA ipsp增强的具体突触前机制是酒精研究的新挑战，也是开发酒精中毒治疗化合物的可能目标。

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.