Ethanol & Anxiety: Cellular Mechanisms

描述(由申请者提供)：本申请的目标是了解慢性酒精暴露、戒酒和调节焦虑症行为的神经生物学机制之间的关系。拟议的实验将利用慢性酒精暴露的大鼠模型，并将结合电生理学、细胞和分子生物学以及行为实验方法来研究特定大脑区域-杏仁外侧核(BLA)在这些过程中的作用。这一大脑区域被广泛认为是控制啮齿动物焦虑样行为的神经回路的重要调节组成部分。此外，前一个资助期的研究结果表明，在BLA的谷氨酸和GABA能神经递质系统中都有广泛的神经生理学适应。因此，当前提案的目标是1)了解支配这些变化的神经生物学和细胞机制，2)确定BLA神经递质系统在调节与慢性酒精暴露和随后的戒断相关的焦虑样行为中的作用。我们提议的实验将专门测试中心假设，即慢性酒精暴露戒断期间的焦虑是由主要杏仁核神经递质系统的功能变化引起的。具体目标1将通过表征慢性间歇性酒精吸入暴露后大鼠谷氨酸神经传递的神经生理和分子变化来检验这一假说。实验方法包括体外切片膜片钳电生理学检测BLA谷氨酸能传入神经元的功能，生化分析谷氨酸受体的表达和定位。特定目标2将检查慢性酒精和戒断相关的改变，在大鼠的BLA，GABA能神经传递和受体的表达。体外切片全细胞电生理学也将用于这一目标。此外，还将使用细胞和分子生物学方法来分析BLA GABA能系统中的分子适应。具体目标3将通过直接研究慢性酒精暴露后焦虑样行为表达增强的BLA谷氨酸和GABA能系统来解决我们的中心假设。拟议的实验将专门研究暴露和戒断时间进程和神经生理功能之间的演变关系。此外，传统的行为药理学方法将被用来更好地理解这种神经生物学功能的变化如何有助于戒断相关焦虑的表达。最终，拟议的实验将更好地确定杏仁核对慢性酒精暴露和戒酒后表现出的焦虑样行为的特定神经生物学贡献。因此，这些研究可以为人类酗酒者焦虑相关复发的细胞机制提供洞察力。公共卫生相关性本研究项目的重点是了解慢性酒精暴露和戒断对调节焦虑等情绪的神经生理过程的影响。一旦该项目完成，我们将更好地了解长期接触乙醇和戒酒是如何改变大脑的。

DESCRIPTION (provided by applicant): The goal of the current application is to understand the relationship between chronic alcohol exposure, withdrawal from this exposure, and the neurobiological mechanisms regulating anxiety-like behavior. The proposed experiments will utilize a rat model of chronic ethanol exposure and will integrate electrophysiological, cellular and molecular biological, and behavioral experimental approaches to examine the role of a specific brain region, the lateral/basolateral amygdala (BLA), in these processes. This brain area has been extensively implicated as an important regulatory component of the neural circuitry controlling anxiety-like behavior in rodents. Furthermore, findings from the previous funding period have shown extensive neurophysiological adaptations in both the glutamatergic and GABAergic neurotransmitter systems in the BLA. The objectives of the current proposal are therefore to 1) understand the neurobiological and cellular mechanisms governing these alterations and 2) define the role of BLA neurotransmitter systems in regulating anxiety-like behavior associated with chronic ethanol exposure and subsequent withdrawal. Our proposed experiments will specifically test the central hypothesis that anxiety during withdrawal from chronic ethanol exposure is caused by functional alterations within the major amygdala neurotransmitter systems. Specific Aim 1 will test this hypothesis by characterizing neurophysiological and molecular alterations in glutamate neurotransmission following a chronic intermittent ethanol inhalation exposure in rats. Experimental approaches include in vitro slice patch-clamp electrophysiology to examine the function of BLA glutamatergic afferents and biochemical analysis of glutamate receptor expression and localization. Specific Aim 2 will examine chronic ethanol- and withdrawal-related alterations in rat BLA GABAergic neurotransmission and receptor expression. In vitro slice whole-cell electrophysiology will be used in this aim as well. In addition, cell and molecular biological approaches will be employed to analyze molecular adaptations in the BLA GABAergic system. Specific Aim 3 will address our central hypothesis by directly examining the BLA glutamatergic and GABAergic systems in the context of enhanced expression of anxiety-like behavior following chronic ethanol exposure. The proposed experiments will specifically examine the evolving relationship between exposure and withdrawal time course and neurophysiological function. Additionally, traditional behavioral pharmacological approaches will be used to better understand how changes in this neurobiological function contribute to the expression of withdrawal-related anxiety. Ultimately, the proposed experiments will better define the specific neurobiological contributions of the amygdala to anxiety-like behavior expressed following chronic alcohol exposure and withdrawal. These studies could therefore provide insight into the cellular mechanisms governing anxiety-associated relapse in human alcoholics. PUBLIC HEALTH RELEVANCE The focus of this research project is to understand the impact of chronic ethanol exposure and withdrawal on neurophysiological processes that regulate emotions like anxiety. Once the project is completed, we will better understand how chronic ethanol exposure and withdrawal alter the brain.