Ethanol Effects on the Mammalian Circadian Clock

描述(申请人提供)：本提案继续我们对乙醇对位于视交叉上核(SCN)的哺乳动物生物钟的影响的研究。饮酒、滥用和戒酒对睡眠和昼夜节律有深远的影响。酒精对这两个过程的影响可能是紧密交织在一起的，因为昼夜节律功能的中断是许多睡眠不规律的主要原因。我们研究的长期目标是更好地了解导致这些睡眠问题的神经过程，特别是关注昼夜节律的作用。我们的合作研究表明，乙醇在体内和体外都抑制了SCN昼夜节律时钟的光相位重置。这项RO1提案的目的是确定乙醇急性影响的细胞机制，并扩大我们的研究，以调查慢性酒精和酒精戒断的影响。我们合作的主要优势是我们能够将互补的体内和体外实验交织在一起，利用每种方法的独特方面。我们的中心假设是，乙醇抑制了SCN核心神经元中的谷氨酸信号，随着时间的推移，这会导致谷氨酸能活动的上调。我们提议的研究的基本原理是，识别乙醇调节生物钟的细胞机制将导致对可能预防或克服这种衰弱疾病的治疗方法的新见解。因此，我们建议追求以下特定目标：特定目标1.确定乙醇对SCN中光/谷氨酸信号的影响的时间依赖性变化：急性与耐受、慢性与戒断。这些实验将通过监测行为和电生理(体内和体外)节律来表征乙醇对SCN昼夜节律的影响，以及这些影响如何随酒精暴露的时间而变化。具体目的2.确定乙醇在SCN中作用的细胞机制。这些实验将评估乙醇对体内SCN神经肽释放模式的影响，并探讨乙醇抑制谷氨酸诱导的体外时相重置的细胞机制。具体目标3.确定乙醇如何影响非光学相位重置。这些实验将评估急性和慢性乙醇以及乙醇戒断对体内和体外5-羟色胺能、GABA能和NPY能时相重置的影响，并探索这些影响发生的机制和位置。 与公共健康相关：酗酒和戒酒对昼夜节律和睡眠有深远影响。这两种现象可能是相互关联的，因为昼夜节律功能的中断是许多睡眠不规律的主要原因。由于睡眠问题既与酒精中毒的发展有关，也与戒酒后复发的可能性有关，因此更好地了解导致这些睡眠问题的神经过程是很重要的。我们研究的目的是描述急性和慢性酒精戒断对昼夜节律的影响，确定这些影响是否源于对生物钟的直接作用，并探讨这些影响的细胞机制。

DESCRIPTION (provided by applicant): This proposal continues our investigation of ethanol effects on the mammalian circadian clock located in the suprachiasmatic nucleus (SCN). Alcohol use, abuse and withdrawal have profound effects on sleep and circadian rhythms. Alcohol effects on these two processes likely are closely intertwined since disruptions in circadian functioning are major causes of many sleep irregularities. The long-term goal of our research is to better understand the neural processes contributing to the etiology of these sleep problems, specifically focusing on the role circadian rhythms. Our collaborative research shows that ethanol inhibits photic phase resetting of the SCN circadian clock in vivo and in vitro. The objective of this RO1 proposal is to identify the cellular mechanisms underlying the acute effects of ethanol, and to expand our research to investigate the effects of chronic alcohol and alcohol withdrawal. The major advantage of our collaboration is our ability to interweave complementary in vivo and in vitro experiments that take advantage of the unique aspects of each approach. Our central hypothesis is that ethanol inhibits glutamate signaling in core SCN neurons, which over time leads to up-regulated glutamatergic activity. Our rationale for the proposed studies is that identifying the cellular mechanisms through which ethanol modulates the circadian clock will lead to new insights on treatments that may prevent or overcome this debilitating disease. Therefore, we proposed to pursue the following specific aims: Specific Aim 1. Determine time-dependent changes in ethanol effects on photic/ glutamate signaling in the SCN: acute vs. tolerance vs. chronic vs. withdrawal. These experiments will characterize the effects of ethanol on the SCN circadian clock through monitoring behavioral and electrophysiological (in vivo and in vitro) rhythms, and how these effects vary depending on the duration of ethanol exposure. Specific Aim 2. Determine the cellular mechanisms of ethanol actions in the SCN. These experiments will assess the effects of ethanol on in vivo SCN neuropeptide release patterns, and investigate the cellular mechanisms through which ethanol inhibits glutamate-induced phase resetting in vitro. Specific Aim 3. Determine how ethanol affects non-photic phase resetting. These experiments will assess the effects of acute and chronic ethanol, and ethanol withdrawal, on serotonergic, GABAergic, and NPYergic phase resetting in vivo and in vitro, and probe the mechanisms and locations through which these effects occur. PUBLIC HEALTH RELEVANCE: Alcohol abuse and withdrawal have profound effects on circadian rhythms and sleep. These two phenomena are likely interrelated, since disruptions in circadian functioning are a major cause of many sleep irregularities. Since sleep problemshave been linked to both the development of alcoholism and the likelihood of a relapse in recovering alcoholics, it is important to better understand the neural processes that contribute to the etiology of these sleep problems. The goal of our research is to delineate the effects of acute and chronic ethanol and ethanol withdrawal on circadian rhythms, determine whether these effects are due to direct actions on the circadian clock, and investigate the cellular mechanisms underlying these effects.