Molecular regulation of CeA glutamate and binge drinking

摘要/项目摘要 酗酒是美国最普遍的酒精中毒形式，但其神经生物学研究表明， 酗酒并不为人所知。我实验室的大量功能数据表明 酒精诱导的细胞核内mGluR 5/Homer 2通路活性增加（通过PI 3 K和PKC）， 乙酰半胱氨酸（NAC）壳对于酗酒小鼠模型中的饮酒倾向很重要 喝酒NAC外壳与其他成员共享细胞结构，解剖学和功能特征。 延伸的杏仁核子回路，包括杏仁核中央核（CeA）-一个高度 与酒精中毒的神经生物学有关Homer 2在CeA中富集，并且其水平在细胞中上调。 与慢性饮酒模型中mGluR 1/5的结果一致。初步功能数据表明， 正如对NAC壳所观察到的，抑制CeA mGluR 5以及PI 3 K活性减少了小鼠的酗酒， 这一发现与现有报告一致，即CeA PKC敲低后限制性酒精摄入量减少。 这些数据表明，mGluR 5介导的信号传导通过PI 3 K和PKC在细胞内也起着重要作用。 CeA在酗酒的调节中，也许还有遗传上的脆弱性。该项目将扩大 这些最近的观察，并采用我们的结合行为药理学和遗传学的方法， 为了验证自发性或酒精诱导的mGluR介导的信号传导增加的过度假设， 通过它的q亚基转化为PKC，通过它的q亚基转化为延伸杏仁核结构内的PI 3 K，特别是CeA， 对于酗酒的表现和遗传易感性很重要。本提案的目标1 将采用药理学和遗传学相结合的方法来测试特定的假设， 通过CeA内的mGluR 5-Homer 2-PI 3 K和mGluR 5-Homer 2-PKC？通路的信号传导是 必要和/或足够的维持小鼠过量的酒精摄入。目标2将这些功能 研究了酗酒史对表达和激活状态的短期和长期影响， mGluR 5介导的杏仁核延伸结构及其前额叶皮质内的信号通路相互关联 地区目的3将基础和酒精刺激的mGluR 5-Homer 2-激酶途径激活与遗传相关性联系起来。 酗酒倾向，使用几种动物模型。预计所取得的成果将大大 增加我们对mGluR/Homer 2介导的信号在延伸杏仁核中的作用的理解 规范了过量饮酒的维持和脆弱性。这样的知识将指向 酒精诱导的mGluR 5/Homer介导的谷氨酸突触后调节的改变 杏仁核结构及其前额叶皮层相互连接的重要性 神经适应调节酗酒倾向，这与理解 酒精中毒的脆弱性和谷氨酸靶向药物治疗。

Abstract/Project Summary Binge alcohol drinking is the most prevalent form of alcoholism within the United States yet the neurobiology of binge drinking is not well-understood. A significant body of functional data from my laboratory demonstrates that alcohol-induced increases in mGluR5/Homer2 pathway activity (via PI3K and PKC¿) within the nucleus accumbens (NAC) shell as important for the propensity to consume alcohol in murine models of binge alcohol drinking. The NAC shell shares cytoarchitectural, anatomical and functional features with other members of the extended amygdala subcircuit, including the central nucleus of the amygdala (CeA) - a brain region highly implicated in the neurobiology of alcoholism. Homer2 is enriched in the CeA and its levels are up-regulated in concert with those of mGluR1/5 in models of chronic alcohol drinking. Preliminary functional data indicates that, as observed for the NAC shell, inhibiting CeA mGluR5, as well as PI3K, activity reduces binge alcohol drinking in mice, a finding consistent with existing reports for a reduction in limited access alcohol intake upon CeA PKC¿ knock-down. Such data point to an important role also for mGluR5-mediated signaling through both PI3K and PKC¿ within the CeA in the regulation of, and perhaps genetic vulnerability to, binge drink. This project will expand upon these recent observations and employ our combination of behavioral pharmacological and genetic approaches to test the over-arching hypothesis that idiopathic or alcohol-induced increases in mGluR-mediated signaling through its ¿q subunit to PKC¿ and its ¿¿ subunit to PI3K within extended amygdala structures, notably the CeA, is important for the manifestation of, and genetic vulnerability to, binge alcohol drinking. Aim 1 of this proposal will employ a combination of pharmacological and genetic approaches to test the specific hypothesis that intact signaling through the mGluR5-Homer2-PI3K and mGluR5-Homer2-PKC¿ pathways within the CeA is necessary and/or sufficient for maintaining excessive alcohol intake in mice. Aim 2 will relate these functional studies to the short- and long-term effects of a history of binge drinking upon the expression and activational state of mGluR5-mediated signaling pathways within extended amygdala structures and their prefrontal cortical interconnected regions. Aim 3 will relate basal and alcohol-stimulated mGluR5-Homer2-kinase pathway activation to genetic propensity to binge drink, using several animal models. It is anticipated that the results obtained will greatly increase our understanding of the role for mGluR/Homer2-mediated signaling within the extended amygdala regulates the maintenance of, and vulnerability to, excessive alcohol drinking. Such knowledge will point to alcohol-induced alterations in mGluR5/Homer-mediated regulation of post-synaptic aspects of glutamate transmission within extended amygdala structures and their prefrontal cortical interconnections as critical neuroadaptations regulating the propensity to binge drink, which has high relevance for understanding of alcoholism vulnerability and its treatment with glutamate-targeting pharmacotherapies.