Ethanol & Anxiety: Cellular Mechanisms

描述(由申请人提供)：目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，如酒精身体依赖后增强的负面影响。我们将通过利用慢性酒精暴露的大鼠模型，并通过整合光遗传学、突触神经生理学和行为实验方法来检查特定大脑区域-杏仁外侧核(BLA)中谷氨酸和GABA能神经传递的适应性，从而实现这一目标。这一大脑区域被广泛认为是神经回路的重要调节成分，控制着慢性酒精暴露戒断时的焦虑行为，以及未接触药物和暴露于药物的动物的奖赏寻求。前一个资金时期的研究结果表明，广泛的谷氨酸和GABA能突触适应发生在特定的突触前和突触后隔区，并可能发生在特定的传入系统中。因此，当前提议的目标是了解支配这些改变的特异性的神经生物学和细胞机制。我们提议的实验将检验这一中心假设，即慢性乙醇后不同BLA传入神经元突触功能的特定变化导致戒断相关焦虑的发展和表达。具体目标1将通过定义慢性酒精暴露和戒断后突触前和突触后改变的区域起源来检验这一假设。我们将利用光遗传学方法来控制来自特定传入的突触传递，以及体外切片膜片钳电生理学。这些研究意义重大，因为它们将首先揭示在酒精身体依赖期间涉及血乳酸变化的特定大脑区域。其次，这些传入信息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慢性酒精暴露可能如何扰乱信息处理。具体目标2将研究BLA神经生理学和慢性间歇性酒精/戒断引起的可塑性状态之间的功能和行为关系。在这种情况下，我们将通过使用体外切片记录直接研究BLA谷氨酸和GABA能突触变化来解决我们的中心假设，该记录是在慢性酒精暴露后焦虑样行为表达增强的背景下解释的。拟议的实验将具体检验使用暴露和戒断时间进程的演变关系。这些研究意义重大，因为它们将确定导致BLA中乙醇条件作用的确切细胞和突触机制。最终，该应用程序将更好地确定杏仁核对慢性酒精暴露和戒酒后焦虑样行为增强的特定神经生物学作用。这些研究将为人类酗酒者控制滥用和复发的潜在细胞机制提供洞察力。

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.