Central Amygdala CART modulates ethanol withdrawal induced anxiety

描述(申请人提供)：酒精依赖是一种普遍的痛苦，每年的社会成本高达数千亿美元。酒精依赖的治疗因许多因素而变得复杂，最明显的是复发。复发行为被认为是由酒精戒断诱导的焦虑(EWIA)引起的。与EWIA密切相关的大脑区域是中央杏仁核(CEA)。损毁中央杏仁核，而不是基底外侧杏仁核，导致戒断过程中酒精消耗量减少。酒精依赖引起的神经生物学改变是普遍存在的；在CEA中，这些改变包括谷氨酸能活性增加和NMDA受体表达。在戒断过程中，这些增加会导致CEA的过度激活；这种过度激活被认为是导致复发的戒断诱导焦虑的中介。可卡因和苯丙胺调节转录本(CART)是一种新的与酒精依赖有关的神经肽。它在CEA中表达，并已被证明在急性戒断时在这里的表达增加。此外，CART，已被报道增强NMDA受体介导的电流。这一提议的首要假设是，CART是EWIA的关键调解人。为了测试这一点，我们将对依赖和戒断过程中CART的表达进行全面的检查。采用慢性乙醇治疗(CET)和慢性间歇乙醇治疗(CIE)两种模型诱导乙醇依赖。CIE含有一种戒断成分，推测它可能涉及戒断诱导的焦虑。野生型(WT)和CART基因敲除(KO)小鼠的依赖倾向将使用CET和CIE进行比较。还将对WT和KO小鼠在戒断0、24和72小时时的EWIA进行检测。还将进行皮质酮ELISA和免疫组织化学检查。应激诱导的饮酒和皮质酮水平对急性应激源的反应也将在WT和KO小鼠之间进行评估和比较。该提案的后半部分将首先在我们手中验证CART的NMDA增强作用，特别是在CEA中。然后，将进行全面的电生理电压钳分析，并比较WT和KO小鼠在戒酒0、24和72小时时乙醇未戒断、CET和CIE小鼠CEA中NMDA受体介导的电流。这些实验的发现将阐明EWIA的基础以及CART在EWIA诱导的复发中的作用。此外，这些结果将为治疗干预和防止依赖酒精和其他滥用药物的个人复发提供新的靶点。

DESCRIPTION (provided by applicant): Ethanol dependence is a widespread affliction with societal costs in the hundreds of billions of dollars every year. Treatment of ethanol dependence is complicated by many factors, most notably relapse. Relapse behaviors are believed to result from ethanol withdrawal-induced anxiety (EWIA). A brain region critically involved in EWIA is the central amygdala (CeA). Lesions of the central, but not basolateral, amygdala resulted in reduced ethanol consumption during withdrawal. Neurobiological alterations induced by ethanol dependence are widespread; in the CeA, these changes include increased glutamatergic activity and NMDA receptor expression. During withdrawal, these increases lead to hyperactivation of the CeA; this hyperactivation is believed to mediate the withdrawal-induced anxiety that underlies relapse. Cocaine- and amphetamine-regulated transcript (CART) is a novel neuropeptide implicatied in ethanol dependence. It is expressed in the CeA and has been shown to increase expression here during acute withdrawal. Additionally, CART, has been reported to potentiate NMDA receptor-mediated currents. The overarching hypothesis of this proposal is that CART is a critical mediator of EWIA. To test this, a comprehensive examination of CART expression during dependence and withdrawal will be conducted. Ethanol dependence will-be induced using two models: chronic ethanol treatment (CET) and chronic intermittent ethanol (CIE). CIE contains a withdrawal component that presumably involves withdrawal induced anxiety. Dependence liability in wild type (WT) and CART knockout (KO) mice will compared using both CET and CIE. An examination of EWIA in the WT and KO mice at 0, 24, and 72 hours withdrawal will also be conducted. Corticosterone ELISAs and immunohistochemistry will be performed as well. Stress induced drinking and corticosterone levles in response to an acute stressor will also be assessed and compared between the WT and KO mice. The second half of this proposal will first verify in our hands, the NMDA potentiating actions of CART, specifically in the CeA. Then, a comprehensive electrophysiological voltage clamp analysis and comparison of NMDA receptor-mediated currents in the CeA of ethanol naive, CET, and CIE mice at 0, 24, and 72 hours withdrawal in WT and KO mice will be performed. The findings from these experiments will elucidate the underpinnings of EWIA and the role of CART in EWIA-induced relapse. Furthermore, these results will provide a novel target for therapeutic intervention and prevention of relapse in individuals dependent on ethanol and possibly other drugs of abuse.