a6 subunit-containing nicotinic receptors in alcohol consumption and reward

描述（由申请人提供）：酒精消费是世界上过早死亡的第三大风险因素[1]。深入了解驱动消费的作用机制将导致更好的戒酒疗法。酒精已被证明能激活中皮质边缘通路内的多巴胺能（DA能）神经元，这是所有其他已知滥用药物激活的主要大脑奖励回路。具体而言，烟碱乙酰胆碱受体（nAChR）与酒精消耗和奖励有关。神经元nAChR是五聚体配体门控离子通道，鉴定了12个不同的亚基（α 2-α 10，β 2-β 4）。亚基组成决定了受体的生物物理和药理学性质。参与酒精消耗和奖励的nAChRs的亚基组成目前尚不清楚。此前，我们的实验室已经表明，含有α 4亚基（α 4* nAChRs）的nAChRs与酒精消耗和奖励密切相关。此外，初步数据表明，参与酒精消费和奖励的nAChRs也可能包含α 6亚基。有趣的是，α 6 nAChR亚基基因CHRNA 6存在多态性，与人类饮酒者的重度饮酒相关[12]。α 6亚基也在腹侧被盖区（VTA）的DA能神经元中高度表达，这是中皮质边缘通路的一部分。因此，我假设α 6* nAChRs参与酒精消费和奖励，以及DA能腹侧被盖区神经元的激活。为了验证这一假设，我将使用药理学，遗传学，电生理学和行为分析。在目标1中，我将使用生物物理的方法在小鼠中脑切片测试的假设，α 6* 乙酰胆碱受体在乙醇诱导的腹侧被盖区DA能神经元的激活发挥关键作用。在目标2中，我将分别使用黑暗中饮酒和条件性位置偏好来衡量酒精消费和奖励。这些试验将与脑区域选择性输注α 6 nAChR拮抗剂和不表达CHRNA 6的遗传小鼠模型联合进行。预计这些实验的结果将为深入了解急性饮酒和奖励的分子机制提供帮助。

DESCRIPTION (provided by applicant): Alcohol consumption is the third largest risk factor for premature mortality in the world [1]. Insights into the mechanism of action that drives consumption will lead to better drinking cessation therapies. Alcohol has been shown to activate dopaminergic (DAergic) neurons within the mesocorticolimbic pathway, the major brain reward circuit activated by all other known drugs of abuse. Specifically, nicotinic acetylcholine receptor (nAChRs) have been implicated in alcohol consumption and reward. Neuronal nAChRs are pentameric ligand gated ion channels, with twelve distinct subunits identified (alpha2-alpha10, beta2-beta4). The subunit composition determines the biophysical and pharmacological properties of the receptor. Subunit composition of nAChRs involved in alcohol consumption and reward are currently unknown. Previously, our lab has shown that nAChRs that contain the alpha4 subunit (alpha 4* nAChRs) are critically involved in alcohol consumption and reward. In addition, preliminary data suggests that nAChRs involved in alcohol consumption and reward may also contain the alpha 6 subunit. Interestingly, there are polymorphisms in the alpha 6 nAChR subunit gene, CHRNA6, associated with heavy alcohol consumption in human drinkers [12]. The alpha 6 subunit is also highly expressed in DAergic neurons in the ventral tegmental area (VTA), which is part of the mesocorticolimbic pathway. Thus, I hypothesize that alpha 6* nAChRs are involved in alcohol consumption and reward, as well as activation of DAergic VTA neurons. To test this hypothesis, I will use pharmacology, genetics, electrophysiology and behavioral assays. In Aim 1, I will use biophysical approaches in mouse midbrain slices to test the hypothesis that alpha 6* nAChRs play a critical role in ethanol-induced activation of VTA DAergic neurons. In Aim 2, I will use drinking- in-the-dark and conditioned place preference to measure alcohol consumption and reward, respectively. These assays will be done in combination with brain region-selective infusions of alpha 6 nAChR antagonists and genetic mouse models that do not express CHRNA6. It is anticipated that the results from these experiments will provide insights into the molecular mechanism underlying acute alcohol consumption and reward.