Ethanol - Anxiety Interaction: Cellular Mechanisms

描述(由申请人提供)：在人类和实验动物模型中，酒精消费的抗焦虑特性和从慢性接触中戒除焦虑的方面都得到了很好的证实。由于这些与焦虑相关的效应有助于加剧酒精滥用，因此详细了解酒精与焦虑相互作用的细胞和分子机制是很重要的。虽然已知在恐惧/焦虑时，大脑的许多区域会相互作用，但杏仁核是边缘前脑的“情绪”中心，是神经焦虑回路的中心组成部分。兴奋性和抑制性神经递质系统之间的微妙平衡控制着这一系统，杏仁核兴奋的增加会导致恐惧/焦虑的增强。使用急性分离的杏仁外侧核/基底外侧核神经元的初步研究表明，慢性乙醇可以改变NMDA型离子型谷氨酸和抑制GABAA受体的功能，而不影响其他神经递质系统。重要的是，这两个受体系统对临床上相关的乙醇浓度都很敏感，这表明它们在慢性暴露期间的功能适应可能是将滥用与焦虑联系起来的细胞底物之一。我们的中心假设是，慢性酒精暴露和随后的戒断会不同地影响主要的杏仁核神经递质系统，这一假设将通过进一步检查大鼠杏仁核外侧/基底外侧的谷氨酸门控离子受体和GABAA受体的表达和功能来检验。具体地说，我们将利用全细胞膜片钳电生理学和单细胞逆转录/聚合酶链式反应(RT-PCR)对急性分离的神经元进行检测。这些研究将与实时RT-PCR一起完成，以表征杏仁外侧核/基底外侧核对慢性酒精暴露和戒断的细胞和分子适应。我们还将通过在体外切片准备中使用杏仁外侧核/基底外侧杏仁核内的全细胞记录来测量突触后和突触前功能，以评估对慢性酒精暴露的适应的生理分支。最后，我们将通过整合戒断过程中的细胞、分子、突触和行为测量来测试受体/突触功能、焦虑和戒断之间的关联。总之，这些研究将对慢性酒精诱导的恐惧/焦虑相关适应机制提供重要的见解，并最终导致对酒精-焦虑相互作用的更好理解。

DESCRIPTION (provided by applicant): The anxiolytic properties of ethanol consumption and anxiogenic aspects of withdrawal from chronic exposure are well established in both humans as well as experimental animal models. Because these anxiety-related effects help potentiate alcohol abuse, it is important to gain a detailed understanding of the cellular and molecular mechanisms that underlie the ethanol-anxiety interaction. While numerous brain regions are known to interact during fear/anxiety, the amygdala, an "emotional" center in the limbic forebrain, is a central component of the neural anxiety circuitry. A delicate balance between excitatory and inhibitory neurotransmitter systems controls this system, with increases in amygdala excitation leading to enhanced fear/anxiety. Preliminary studies of using acutely isolated neurons from the lateral/basolateral amygdala indicate that chronic ethanol can alter NMDA-type ionotropic glutamate and inhibitory GABAA receptor function while sparing other neurotransmitter systems. Importantly, both receptor systems are sensitive to clinically relevant ethanol concentrations, indicating their functional adaptation during chronic exposure may be among the cellular substrates relating abuse with anxiety. Our central hypothesis, that chronic ethanol exposure and subsequent withdrawal differentially affect major amygdala neurotransmitter systems, will be tested by further examination of glutamate-gated ionotropic receptor and GABAA receptor expression and function within the rat lateral/basolateral amygdala. Specifically, we will utilize whole-cell patch clamp electrophysiology and single-cell reverse transcription/polymerase chain reaction (RT-PCR) with acutely isolated neurons. These studies will be done along with real-time RT-PCR to characterize cellular and molecular adaptations in the lateral/basolateral amygdala to chronic ethanol exposure and withdrawal. We will also assess the physiological ramifications of adaptations to chronic ethanol exposure by measuring post- and pre-synaptic function using whole-cell recordings within lateral/basolateral amygdala in in vitro slice preparations. Finally, we will test the association between receptor/synaptic function, anxiety, and withdrawal by integrating cellular, molecular, synaptic and behavioral measures during a withdrawal time course. Together, these studies will provide important insight into the mechanisms associated with chronic ethanol-induced adaptations related to fear/anxiety and eventually lead to a better understanding of the ethanol-anxiety interaction.