Mechanisms of Alcohol Withdrawal

项目摘要 酒精戒断（WD）会产生一系列危险的临床症状，包括强烈的癫痫发作。 癫痫发作背后的过度兴奋是由一系列内在膜特性产生的， 用乙醇（EtOH）破坏。先前的工作已经证明，慢性乙醇暴露和WD产生 离子通道蛋白的上调和促进WD发作的功能的获得。剩余的差距 我们对WD相关癫痫发作的理解是一个可测试的模型， 上下文WD在中线丘脑核中产生上调和增加的爆发。在海马体中， 哺乳动物雷帕霉素靶蛋白复合物1（mTORC 1）在WD期间在CA 1神经元中被激活，抑制 Kv1.1的翻译，并导致抑制减少，我们假设这将允许丘脑的侵袭。 爆发和癫痫样群体放电增加。我们开发了一种新的网络模型 兴奋性，这将使我们能够研究的出现，时间进程和分子基础的EtOH WD 过度兴奋和癫痫发作。我们将解决以下目标：在目标1中，我们将确定内在的 由于乙醇WD，导致中线丘脑和CA 1中膜过度兴奋的性质 癫痫。在体外制备中使用电压钳记录结合药理学方法， 我们将确定WD的癫痫样放电是否最终依赖于进行性的 丘脑兴奋性爆发性放电（依赖于PKC）与K+电流减少之间的不平衡 在CA 1锥体细胞（由mTOR控制）中。在目标2中，我们将确定重要的监管机构， EtOH WD发作时丘脑和CA 1区树突兴奋性。mTOR信号转导与 发展的自发性癫痫发作，我们显示的数据，它是活跃的WD。使用 分子方法，我们将在蛋白质合成存在和不存在的情况下切换mTOR活性 抑制剂的我们将测试mTORC是否抑制Kv1.1的翻译，正如我们的初步数据所建议的那样。 在目标3中，我们将细胞和分子研究结果结合起来，以确定WD介导的 体内网络兴奋性和癫痫易感性的变化。使用一种新的光遗传学方法，我们将 测试在WD期间刺激丘脑-HC通路是否会引起增强的癫痫样活动 与依赖于易化CA 1突触的模式化活动的对照相比。我们预计 mTORC 1的破坏将改变或逆转WD介导的兴奋性。癫痫发作阈值显著高于 在重复EtOH WD期间减少，我们将利用这一事实来检验药物有效对抗 WD诱导的过度兴奋也将有效地将癫痫发作阈值提高到基线水平。成功 这些实验将提供一个更全面的理解，如何短暂的纺锤体事件和穗 波复合物促进或支持强直-阵挛性WD发作-这可能导致新的 途径和相关的药物靶点，这将提供一种预防WD发作的方法， 治疗它。

PROJECT SUMMARY Alcohol withdrawal (WD) produces a range of dangerous clinical symptoms, including intense seizures. Hyperexcitability underlying seizures is produced by an array of intrinsic membrane properties that are disrupted by ethanol (EtOH). Prior work has demonstrated that chronic EtOH exposure and WD produce an up-regulation of ion channel proteins and a gain of function that promotes WD seizure. A remaining gap in our understanding of WD-related seizure is a testable model that places cellular changes in a network context. WD produces upregulation and increased bursting in midline thalamic nuclei. In hippocampus, mammalian target of rapamycin Complex 1 (mTORC1) is activated in CA1 neurons during WD, represses translation of Kv1.1, and results in reduced inhibition that we hypothesize will allow invasion of thalamic bursts and increased epileptiform population discharges. We have developed a new model of network excitability that will allow us to study the emergence, time course and molecular underpinnings of EtOH WD hyperexcitability and seizure. We will address the following aims: In Aim 1, we will determine the intrinsic properties contributing to membrane hyperexcitability in midline thalamus and CA1 due to ethanol WD seizure. Using voltage clamp recordings in an in vitro preparation coupled with pharmacological approaches, we will determine whether epileptiform discharges in WD are ultimately dependent on a progressive imbalance between excitatory burst discharges in thalamus (which depend on PKC), and reduced K+ currents in CA1 pyramidal cells (which are controlled by mTOR). In Aim 2, we will Determine important regulators of dendritic excitability in thalamus and CA1 in EtOH WD seizure. mTOR signaling is implicated in the development of spontaneous seizures in epilepsy, and we show data that it is active during WD. Using molecular approaches, we will toggle mTOR activity in the presence and absence of protein synthesis inhibitors. We will test whether mTORC represses translation of Kv1.1, as suggested by our preliminary data. In Aim 3, we bring together the cellular and molecular findings to determine the effects of WD-mediated changes to network excitability and seizure susceptibility in vivo. Using a novel optogenetic approach, we will test whether stimulation of the thalamo-HC pathway during WD will elicit enhanced epileptiform activity compared to controls that will depend on patterned activity at facilitated CA1 synapses. We expect that disruptions of mTORC1 will modify or reverse WD-mediated excitability. Seizure threshold is significantly reduced during repeated EtOH WD and we will use this fact to test the hypothesis that drugs effective against WD-induced hyper-excitability will also be effective at raising seizure thresholds to baseline levels. Success in these experiments will provide a more comprehensive understanding of how brief spindle episodes and spike wave complexes promote or support tonic-clonic WD seizures – which could lead to the identification of novel pathways and associated drug targets that will provide a means to prevent WD seizure, and to more effectively treat it.