CREB, Alcohol Reward and Consumption in ENT1 Null Mice

描述（由申请方提供）：乙醇抑制培养细胞中的1型平衡型核苷转运蛋白（ENT 1）。对ENT 1缺失小鼠的初步研究表明，ENT 1也是乙醇在体内的靶点，因为ENT 1缺失小鼠对乙醇的急性作用的反应较低。ENT 1敲除小鼠也比野生型同窝出生的小鼠消耗更多的乙醇。初步研究表明，谷氨酸驱动的CREB激活在ENT 1敲除小鼠的纹状体中增加。这似乎是由于纹状体突触前腺苷A1受体的激活减少，由于腺苷张力降低，通过电生理学研究测量。由于纹状体CREB激活与药物奖励减少有关，ENT 1基因敲除小鼠过量饮酒可能与乙醇奖励耐受性有因果关系。与这一假设一致，条件性位置偏好研究表明，ENT 1基因敲除小鼠对乙醇配对侧（2.0 g/kg）的偏好显著低于野生型小鼠。这项建议将扩大初步研究，并检查CREB信号在调节ENT 1基因敲除小鼠对酒精的行为反应中的作用。首先，将使用初始敏感性、急性和慢性耐受性、操作性自我给药和位置调节试验来检查乙醇耐受性以及乙醇的奖励和强化作用。第二，CREB活性的增加将在特定细胞中使用CRE-lacZ报告小鼠和通过检查ENT 1缺失小鼠纹状体中两种CRE-driven基因（脑啡肽和强啡肽）的表达来鉴定。第三，pCREB免疫反应性将用于测量纹状体脑切片中的CREB活性，以鉴定有助于ENT 1缺失小鼠中基础CREB活性增加的信号传导途径。最后，我们将确定是否在纹状体pCREB的增加占信号通路的改变有助于耐受乙醇的奖励作用和增加ENT 1基因敲除小鼠的乙醇消耗。该项目的目标是了解ENT 1基因敲除小鼠增强饮酒行为的信号通路，并确定酒精中毒的新治疗靶点。

DESCRIPTION (provided by applicant): Ethanol inhibits the type 1 equilibrative nucleoside transporter (ENT1) in cultured cells. Preliminary studies with ENT1 null mice indicate that ENT1 is also a target for ethanol in vivo since ENT1 null mice are less responsive to acute effects of ethanol. ENT1 null mice also consume more ethanol than wild type littermates. Preliminary studies demonstrate that glutamate-driven CREB activation was increased in the striatum of ENT1 null mice. This appears to result from diminished activation of striatal presynaptic adenosine A1 receptors due to reduced adenosine tone as measured by electrophysiological studies. Since striatal CREB activation is associated with reduced drug reward, excessive ethanol drinking in ENT1 null mice may be causally related to tolerance to ethanol reward. Consistent with this hypothesis, a conditioned place preference study demonstrated that ENT1 null mice prefer the ethanol-paired side (2.0 g/kg) significantly less than wild type mice. This proposal will expand upon preliminary studies and examine the role of CREB signaling in regulating behavioral responses to alcohol in ENT1 null mice. First, initial sensitivity, acute and chronic tolerance, operant self-administration, and place conditioning assays will be used to examine ethanol tolerance, and rewarding and reinforcing effects of ethanol. Second, increases in CREB activity will be identified in specific cells using CRE-lacZ reporter mice and by examining expression of two CRE-driven genes, enkephalin and dynorphin, in the striatum of ENT1 null mice. Third, pCREB immunoreactivity will be used to measure CREB activity in striatal brain slices to identify signaling pathways that contribute to increased basal CREB activity in ENT1 null mice. Finally, we will determine whether alterations in signaling pathways that account for increased striatal pCREB contribute to tolerance to rewarding effects of ethanol and increased ethanol consumption in ENT1 null mice. The goal of this project is to understand signaling pathways underlying enhanced alcohol drinking behavior in ENT1 null mice and to identify novel therapeutic targets for alcoholism.