The Alpha-1 GABAA Receptor Regulates Alcohol-Drinking Behaviors

描述(由申请人提供)：众所周知，乙醇[Etoh]的奖赏特性部分是由GABAA受体机制介导的；然而，直到最近的研究才表明，A1受体亚单位，特别是腹侧苍白球[VP]内的那些，可能是调节Etoh增强的关键GABA能受体。这项建议的主要目标将是通过结合神经心理药理学和分子生物学技术，进一步评估包含GABAA A1的受体亚单位在调节乙醇寻找行为中的作用。为了实现这一目标，将使用选择性培育的高酒精饮酒[HAD-1]大鼠。有待检验的主要假设是，选择性抑制HAD-1大鼠VP内包含GABAA A1受体亚单位的亚基将导致选择性减少乙醇动机行为，而对蔗糖动机行为几乎没有影响。对GABAA A1亚单位的抑制将通过构建单纯疱疹病毒[HSV]载体来实现，该载体将利用siRNA序列特异的转录后基因沉默机制。然后将该载体通过双侧引导管直接注入HAD-1大鼠的VP。假设在将载体介导的siRNA扩增子注入VP后，将观察到乙醇维持的反应选择性减少。具体地说，增强剂和神经解剖学的特异性将是预期的，因为既不会在VP中注射活性病毒后对蔗糖的抑制保持反应，也不会期望抑制将活性病毒注入神经解剖控制点[例如尾壳核]的酒精反应。在随后的研究中，将结合原位逆转录-聚合酶链式反应、免疫组织化学和免疫印迹分析[免疫印迹]来确定HSV-siRNA病毒载体操作的成功。这些研究应该扩大我们对GABAA A1受体亚型在酒精饮酒行为调控中的作用的理解。

DESCRIPTION (provided by applicant): It is well established that the rewarding properties of ethanol [EtOH] are mediated in part by GABAA-receptor mechanisms; however, only recently has research demonstrated that the a1 receptor subunit, particularly those within the ventral pallidum [VP], may be the critical GABAergic receptor regulating EtOH reinforcement. The primary objective of this proposal will be to further evaluate the role of the GABAA a1-containing receptor subunit in regulating EtOH-seeking behaviors by employing a combination of neuropsychopharmacological and molecular biology techniques. To accomplish this goal, the selectively-bred high alcohol-drinking [HAD-1] rats will be used. The primary hypothesis to be tested is that a selective inhibition of the GABAA a1 receptor containing subunit within the VP of HAD-1 rats will lead to selective reductions in EtOH-motivated behavior, with little or no effect on sucrose-motivated behaviors. The inhibition of the GABAA a1 subunit will be accomplished by constructing a herpes simplex virus [HSV] vector, which will utilize the siRNA sequence specific, posttranscriptional gene silencing mechanism. This vector will then be infused directly into the VP of HAD-1 rats via bilateral guide cannulae. It is hypothesized that a selective reduction in EtOH-maintained responding will be observed following infusion of the vector-mediated siRNA amplicon into the VP. Specifically, reinforcer and neuroanatomical specificity will be expected, as neither suppression on sucrose maintained responding following infusion of the active virus in the VP, nor suppression on alcohol responding infusion of the active virus into the neuroanatomical control locus [e.g., caudate putamen] will be expected. In subsequent studies, a combination of in situ reverse transcriptase-PCR, immunohistochemistry, and Western analyses [immunoblotting] will be used to determine the success of the HSV-siRNA viral vector manipulations. These studies should extend our understanding of the role of the GABAA a1 receptor subtype in the regulation of alcohol-drinking behaviors.