NEUROSTEROID MODULATION OF ETHANOL WITHDRAWAL SEVERITY

神经活性类固醇3 α -羟基-5 α -孕酮-20- 1 （3 α， 5 α -差异孕酮）是GABAA受体的有效正调节剂。与3alpha， 5alpha-P可能是一种生理上重要的神经调节剂的推测一致，在选择性繁殖的戒断发作易发（WSP）和抗发作（WSR）小鼠中进行的初步研究发现，内源性3alpha， 5alpha-P水平降低或敏感性降低可能与乙醇戒断严重程度增加有关。停用etoh的WSPs对3α， 5- α - p的敏感性降低，内源性3α， 5- α - p的敏感性降低。这将导致在EtOH戒断期间WSP线的神经兴奋性增强。本提案将采用多学科的方法来检验EtOH戒断严重程度的遗传差异部分是由于对，3 - α， 5- α - p的敏感性和/或生物合成的改变。与Specific Aims 1和2相关的研究将确定EtOH戒断严重程度与慢性EtOH诱导的内源性3α， 5α - p浓度、3α， 5α - p生物合成酶，5α -还原酶活性和/或基因表达改变之间的时间关系。在EtOH戒断期间5 - α还原酶抑制的生理后果将在特异性目标2中进行检查。与Specific Aims 4和5相关的研究将确定GABAA受体对3alpha， 5alpha-P的行为敏感性与对3alpha， 5alpha-P的功能敏感性之间的对应关系。行为、生化和分子策略的联合使用将确定3alpha， 5alpha-P作为EtOH戒断严重程度的神经调节剂的重要性。此外，在EtOH戒断期间，对3alpha， 5alpha-P的敏感性和/或生物合成的选择系的差异将提供额外的证据，证明改变大脑局部神经活性类固醇环境可以不同地调节GABAA受体（即WSP和WSR），并导致WSP与WSR在EtOH戒断期间更大的神经兴奋性。这项研究的长期目标是了解对慢性酒精的有害反应（即，身体依赖导致戒断发作）是如何在基因水平上调节的。这些信息不仅有助于我们理解酒精戒断的机制，而且有助于制定治疗酒精依赖的新策略。

The neuroactive steroid 3alpha-hydroxy-5alpha-pregnan-20-one (3alpha, 5alpha-Por allopregnanolone) is a potent positive modulator of GABAA receptors. Consistent with the speculation that 3alpha, 5alpha-P may represent a physiologically significant neuromodulator, preliminary studies in the selectively bred Withdrawal Seizure-Prone (WSP) and- Resistant (WSR) mice found that lower endogenous levels of, or decreased sensitivity to, 3alpha, 5alpha-P may be correlated with increased ethanol (EtOH) withdrawal severity. In EtOH-withdrawing WSPs, the reduced sensitivity to 3alpha, 5-alpha-P, as well as the decrease in endogenous 3alpha, 5alpha-P. This would lead to greater neural excitability in the WSP line during EtOH withdrawal. The present proposal will use a multi-disciplinary approach to test the hypothesis that genetic differences in EtOH withdrawal severity are due in part, to alterations in sensitivity, to and/or biosynthesis of, 3alpha, 5-alpha-P. Studies related to Specific Aims 1 and 2 will determine the temporal relationship between EtOH withdrawal severity and the chronic EtOH- induced alterations in endogenous 3alpha, 5alpha-P concentration and activity and/or gene expression of the 3alpha, 5alpha-P biosynthetic enzyme, 5alpha-reductase. The physiological consequences of 5alpha- reductase inhibition during EtOH withdrawal will be examined in Specific Aim 2. Studies related to Specific Aims 4 and 5 will determine the correspondence between behavioral sensitivity to 3alpha, 5alpha-P and functional sensitivity of GABAA receptors to 3alpha, 5alpha-P. The combined use of behavioral, biochemical and molecular strategies will determine the importance of 3alpha, 5alpha-P as a neuromodulator of EtOH withdrawal severity. Further, the demonstration of selected line differences in sensitivity to, and/or biosynthesis of, 3alpha, 5alpha-P during EtOH withdrawal will provide additional evidence that altering the local neuroactivity steroid environment in the brain can differentially modulate GABAA receptors (i.e., WSP and WSR) and lead to the greater neural excitability in the WSP versus WSR line during EtOH withdrawal. The long term goal of this research is to understand mechanisms underlying how deleterious responses to chronic alcohol (i.e., physical dependence leading to withdrawal seizures) are regulated at the genetic level. Not only will this information aid in our understand of the mechanisms underlying alcohol withdrawal, but this knowledge would help in the development of new strategies for the treatment of alcohol dependence.