Ethanol & Anxiety: Cellular Mechanisms

描述（由申请人提供）：当前申请的总体目标是了解有助于赋予病理行为的神经生物学机制，如乙醇身体依赖后增强的负面影响。我们将利用慢性乙醇暴露的大鼠模型，并结合光遗传学、突触神经生理学和行为实验方法来检查特定脑区域（外侧/基底外侧杏仁核（BLA））的适应性谷氨酸能和gaba能神经传递。这一脑区被广泛认为是神经回路的一个重要调控组成部分，它既控制从慢性乙醇暴露中戒断时的焦虑样行为，也控制未接触药物和暴露药物的动物的寻求奖励行为。先前资助期的研究结果表明，广泛的谷氨酸能和gaba能突触适应发生在特定的突触前和突触后区室中，并可能发生在特定的传入系统中。因此，当前建议的目标是了解控制这些改变特异性的神经生物学和细胞机制。我们提出的实验将验证一个中心假设，即在慢性乙醇后，不同BLA传入事件的突触功能的特异性改变导致戒断相关焦虑的发展和表达。特异性目标1将通过定义慢性乙醇暴露和戒断后表达的突触前和突触后改变的区域起源来验证这一假设。我们将利用光遗传学方法来控制由特定传入事件引起的突触传递，以及体外切片膜片钳电生理学。这些研究具有重要意义，因为它们将首先涉及乙醇生理依赖期间涉及BLA改变的特定大脑区域。其次，这些事件携带着独特的信息形式；因此，任何特定区域的参与都将首次确定长期接触乙醇是如何扰乱信息处理的。具体目标2将检查BLA神经生理学与慢性间歇性乙醇/戒断引起的可塑性样状态之间的功能和行为关系。在这种情况下，我们将通过直接检查BLA谷氨酸能和gaba能突触改变来解决我们的中心假设，使用体外切片记录在慢性乙醇暴露后焦虑样行为表达增强的背景下解释。提出的实验将专门研究使用暴露和戒断时间过程的演变关系。这些研究具有重要意义，因为它们将确定导致BLA中乙醇调节的精确细胞和突触机制。最终，该应用程序将更好地定义杏仁核对慢性酒精暴露和戒断后增强的焦虑样行为的特定神经生物学贡献。这些研究将深入了解人类酗酒者滥用和复发的潜在细胞机制。

DESCRIPTION (provided by applicant): The overall goal of the current application is to understand the neurobiological mechanisms that help confer pathological behaviors like enhanced negative affect following ethanol physical dependence. We will accomplish this goal by utilizing a rat model of chronic ethanol exposure and by integrating optogenetic, synaptic neurophysiology, and behavioral experimental approaches to examine adaptations glutamatergic and GABAergic neurotransmission in a specific brain region, the lateral/basolateral amygdala (BLA). This brain area has been extensively implicated as an important regulatory component of the neural circuitry controlling both anxiety-like behavior during withdrawal from chronic ethanol exposure as well as reward-seeking in drug- naive and -exposed animals. Findings from the previous funding period have demonstrated that the extensive glutamatergic and GABAergic synaptic adaptations occur within specific pre- and postsynaptic compartments and potentially within specific afferent systems. The objectives of the current proposal are therefore to understand the neurobiological and cellular mechanisms governing the specificity of these alterations. Our proposed experiments will test the central hypothesis that specific alterations in synaptic function at distinct BLA afferents following chronc ethanol lead to the development and expression of withdrawal-related anxiety. Specific Aim 1 will test this hypothesis by defining the regional origin for pre- and post-synaptic alterations expressed following chronic ethanol exposure and withdrawal. We will utilize optogenetic approaches to control synaptic transmission arising from specific afferents along with in vitro slice patch-clamp electrophysiology. These studies are significant because they will first implicate specific brain regions involved in BLA alterations during ethanol physical dependence. Second, these afferents carry unique forms of information; so any region-specific involvement will identify for the first time how information processing may be disrupted by chronic ethanol exposure. Specific Aim 2 will examine the functional and behavioral relationships between BLA neurophysiology and the plasticity-like state resulting from chronic intermittent ethanol/withdrawal. In this case, we will address our central hypothesis by directly examining BLA glutamatergic and GABAergic synaptic alterations using in vitro slice recordings interpreted in the context of enhanced expression of anxiety-like behavior following chronic ethanol exposure. The proposed experiments will specifically examine the evolving relationship using exposure and withdrawal time courses. These studies are significant because they will identify the precise cellular and synaptic mechanisms leading to ethanol conditioning in the BLA. Ultimately, the application will better define specific neurobiological contributions by the amygdala to enhanced anxiety-like behavior following chronic alcohol exposure and withdrawal. These studies will provide insight into potential cellular mechanisms governing abuse and relapse in human alcoholics.