Ethanol Dependence Induced Changes in Dopamine Signaling in Basolateral Amygdala

 描述（由申请人提供）：本申请的总体目标是了解有助于赋予病理行为（如乙醇身体依赖后增强的负面影响）的神经生物学机制。最近的研究表明，内在外侧/基底外侧杏仁核（BLA）GABA能神经元严格控制的表达的负面情绪，包括那些在退出慢性乙醇暴露后表达。来自腹侧被盖/黑质背侧部的多巴胺能输入已被证明可调节该GABA能系统并解除对驱动焦虑样行为表达的BLA主神经元的抑制。基于强有力的初步证据，我们提出的实验将测试中心假设，即乙醇依赖通过这些GABA能神经元的多巴胺能调节失调来抑制BLA输出。我们将测试我们的中心假设，并实现我们的总体目标，利用一个完善的大鼠模型的慢性乙醇暴露和整合光遗传学，前和突触后多巴胺神经生理学，和行为实验方法。BLA被广泛认为是神经回路的重要调节成分，控制慢性乙醇暴露戒断期间的焦虑样行为以及药物初治和暴露动物的奖赏寻求。具体目标1将通过检查乙醇依赖戒断过程中突触前多巴胺的功能来检验我们的中心假设。我们将直接测量DA释放和再摄取在体外通过整合在体外快速扫描循环伏安法与光遗传学控制DA释放和慢性乙醇暴露。我们假设，根据我们以前的出版物，慢性乙醇暴露将差异调节基础或'强直' DA水平和阶段性DA释放，最终增强DA信号。具体目标2将研究如何突触后DA受体功能改变BLA使用体外全细胞膜片钳电生理学与创新的光遗传学方法来测量突触后DA受体信号。我们的工作假设是，乙醇的身体依赖性将增加突触后D1和D2样DA受体信号，使DA介导的GABA能功能的抑制上调。具体目标3将通过整合DA释放的光遗传学控制与BLA依赖性行为的体内测量，在整个动物环境中对DA信号传导的依赖性的详细细胞效应。我们的工作假设是，多巴胺神经传递和信号的依赖相关变化最终控制戒断依赖性焦虑样行为。拟议的工作采用了一种独特的和高度集成的实验方法，以提供无与伦比的洞察力的神经生物学机制，慢性乙醇暴露的负面强化作用。最终，这些研究将提供对人类酗酒者滥用和复发的潜在细胞机制的深入了解。

 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. Recent studies suggest that intrinsic lateral/basolateral amygdala (BLA) GABAergic neurons tightly control the expression of negative emotions including those expressed during withdrawal following chronic ethanol exposure. Dopaminergic inputs from the ventral tegmentum/substantia nigra pars compacta have been shown to regulate this GABAergic system and disinhibit BLA principal neurons which drive the expression of anxiety-like behaviors. Based on strong preliminary evidence, our proposed experiments will test the central hypothesis that ethanol dependence dis-inhibits BLA output by dysregulating dopaminergic modulation of these GABAergic neurons. We will test our central hypothesis and accomplish our overall goal by utilizing a well- established rat model of chronic ethanol exposure and by integrating optogenetic, pre- and post-synaptic dopamine neurophysiology, and behavioral experimental approaches. The BLA 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-naïve and -exposed animals. Specific Aim 1 will test our central hypothesis hypothesis by examining presynaptic dopamine function during withdrawal from ethanol dependence. We will directly measure DA release and reuptake in vitro by integrating in vitro fast-scan cyclic voltammetry with optogenetic control of DA release and chronic ethanol exposure. We hypothesize that, based on our previous publications, chronic ethanol exposure will differentially modulate basal or `tonic' DA levels and phasic DA release to ultimately enhance DA signaling. Specific Aim 2 will examine how postsynaptic DA receptor function is altered in the BLA using in vitro whole cell patch clamp electrophysiology with innovative optogenetic approaches to measure postsynaptic DA receptor signaling. Our working hypothesis is that ethanol physical dependence will increase postsynaptic D1- and D2-like DA receptor signaling such that DA-mediated inhibition of GABAergic function is up-regulated. Specific Aim 3 will place the detailed cellular effects of dependence on DA signaling within a whole-animal context by integrating optogenetic control of DA release with in vivo measures of BLA-dependent behaviors. Our working hypothesis is that dependence-related changes in dopamine neurotransmission and signaling ultimately control withdrawal-dependent anxiety-like behavior. The proposed work employs a unique and highly integrated experimental approach to provide unparalleled insight into the neurobiological mechanisms governing the negative reinforcing effects of chronic ethanol exposure. Ultimately, these studies will provide insight into potential cellular mechanisms governing abuse and relapse in human alcoholics.