Dissecting the Role of Prefrontal Circuitry in Basolateral Amygdala Physiology and Regulation of Anxiety Following Chronic Ethanol Exposure and Withdrawal

项目总结 戒酒期间焦虑增加是酒精依赖的一个主要特征，一直以来 据报道，这是酒精依赖者复发的常见潜在原因，这是一个关键障碍 对他们的治疗。酒精依赖的动物模型同样显示出焦虑样行为在 酒精戒断，表明他们是一个有效的翻译模式。外侧/基底外侧杏仁核(BLA) 被认为是调节许多情绪行为的神经回路的关键组成部分， 包括焦虑。我们的实验室最近表明，长期接触和戒断酒精会产生 BLA中明显的突触改变，这些变化是特定于输入和计时的。例如，谷氨酸能传入 沿着BLA内侧边界到达终纹(ST)表示一种突触前可塑性 这在酒精暴露的早期就会发生，而输入通过外囊(EC)沿着 在酒精暴露后，BLA的侧缘表达突触后增强。这些数据表明 这种最初的突触前易化的ST输入可能是至关重要的发展的行为和生理 在长期接触酒精的过程中形成的特征。然而，关于具体到什么程度，人们知之甚少 来自不同上游大脑区域的信息输入受到慢性酒精暴露的影响或这些影响的方式 在戒酒过程中独立影响焦虑。在目前的NRSA提案中，我们将审查 从内侧前额叶皮质(MPFC)和无颗粒岛叶皮质(AI)投射到BLA 通过这两条解剖学上截然不同的途径到达血乳酸。因此，这项培训提案的总体目标是 了解大脑中脑区的mPFC和/或AI输入是否经历相似或独特的突触改变 在慢性酒精暴露/戒断后，以及它们是否对表达 戒断引起的焦虑样行为。我们的中心假设是，早期的突触前易化ST- 来自mPFC输入的血乳酸对于随后的神经生理学和行为后果是必要的 慢性酒精暴露和戒断。我们将通过两个具体目标来解决这一假设。在目标1中， 我们将使用DREADD技术在慢性酒精中毒期间的不同时间操作这些BLA输入 暴露，并使用各种焦虑分析，包括高架加迷宫和明/暗盒子。我们的 假说是，慢性酒精暴露期间mPFC-BLA输入的早期促进介导了戒断- 诱发焦虑样行为。利用这些相同的动物，在目标2中，我们将使用全细胞膜片钳 电生理学和光遗传学来表征前和后两者之间的时间生理关系 慢性酒精暴露和戒断后ST-和EC-BLA突触的突触后增强。 对特定大脑区域的识别可能会为更有效的治疗带来潜在的新靶点 在临床环境中酒精戒断引起的焦虑。

PROJECT SUMMARY Increased anxiety during alcohol withdrawal is a central characteristic of alcohol dependence and has been reported as a common, underlying cause of relapse in those with alcohol dependence, which is a critical barrier to their treatment. Animal models of alcohol dependence likewise show increased anxiety-like behaviors during alcohol withdrawal, suggesting they are a valid translational model. The lateral/basolateral amygdala (BLA) has been identified as a critical component of the neural circuitry that regulates many emotional behaviors, including anxiety. Our laboratory has recently shown that chronic ethanol exposure and withdrawal produce distinct synaptic alterations in the BLA that are input- and timing-specific. For example, glutamatergic afferents arriving within the stria terminalis (ST) along the medial BLA boundary express a presynaptic form of plasticity that develops early during alcohol exposure, whereas inputs arriving via the external capsule (EC) along the lateral boarder of the BLA express postsynaptic potentiation later in alcohol exposure. These data suggest that this initial presynaptic facilitation of ST inputs may be crucial for development of the behavioral and physiologic characteristics that develop during prolonged ethanol exposure. However, little is known about how specific inputs from distinct upstream brain regions are affected by chronic ethanol exposure or how these might independently influence anxiety during alcohol withdrawal. In the current NRSA proposal, we will examine inputs to the BLA from the medial prefrontal cortex (mPFC) and the agranular insular cortex (AI), which project to the BLA via these two anatomically distinct pathways. Thus, the overall goal of this training proposal is to understand whether the mPFC and/or AI inputs to the BLA undergo similar or unique synaptic alterations following chronic ethanol exposure/withdrawal, and whether they are necessary for the expression of withdrawal-induced anxiety-like behavior. Our central hypothesis is that early presynaptic facilitation of the ST- BLA from mPFC inputs is necessary for the subsequent neurophysiologic and behavioral consequences of chronic ethanol exposure and withdrawal. We will address this hypothesis through two Specific Aims. In Aim 1, we will use DREADD technology to manipulate these BLA inputs at different times during chronic ethanol exposure and use a variety of anxiety assays including the elevated plus maze and light/dark box. Our hypothesis is that early facilitation of mPFC-BLA inputs during chronic ethanol exposure mediate withdrawal- induced anxiety-like behavior. Using these same animals, in Aim 2, we will employ whole-cell patch clamp electrophysiology and optogenetics to characterize the temporal physiological relationships between pre- and postsynaptic potentiation of ST- and EC-BLA synapses following chronic ethanol exposure and withdrawal. The identification of specific brain regions might lead to potential novel targets for more effective treatments of alcohol withdrawal-induced anxiety in the clinical setting.