The Role of Dopamine Transporter Trafficking in Psychostimulant Addiction

描述（由申请人提供）：精神兴奋剂成瘾在美国是一个普遍存在的问题，影响了数百万人，造成了工资和医疗费用的巨大损失。安非他明和可卡因主要通过阻断单胺的再摄取而起作用，而单胺的再摄取是由钠和氯依赖的质膜转运体促进的5 -羟色胺、去甲肾上腺素和多巴胺。虽然这些精神兴奋剂对单胺转运体具有等摩尔亲和力，但这些药物的增强特性被认为主要是由它们与多巴胺转运体（DAT）的相互作用介导的。最近的体外和体内研究表明，除了抑制DAT功能外，安非他明和可卡因还通过膜运输调节DAT细胞表面水平。我们实验室的初步研究表明，安非他明诱导的细胞表面数据丢失是通过提高数据内在化率发生的。然而，尚不清楚精神兴奋剂引起的DAT表面表达的变化是否与成瘾过程有关。这是由于缺乏可用的动物模型来验证这一假设。我们最近在DAT羧基端发现了横跨587-596残基的10个氨基酸区域，这是基础和蛋白激酶c刺激的DAT内吞作用所必需的。我们建议测试精神兴奋剂介导的数据传输是否需要精神兴奋剂的奖励特性。为此，我们的目标是产生表达内吞缺陷DAT的DAT敲入小鼠。由此产生的小鼠将被评估安非他明的自我给药、条件位置偏好和致敏性，以测试DAT贩运是否在精神兴奋剂的奖励特性中起作用。此外，这些动物将成为未来研究DAT运输在突触传递和多巴胺能可塑性中的作用的宝贵工具。精神兴奋剂滥用和成瘾在美国是一个日益严重的问题，在过去几年中达到了近乎流行病的程度。尽管对精神兴奋剂成瘾的机制进行了大量的调查，但我们的知识仍有很大的差距。目前的建议旨在开发一种动物模型，其中安非他明在大脑中的目标被修改，以确定安非他明对这些目标蛋白质的作用是否有助于成瘾过程。

DESCRIPTION (provided by applicant): Psychostimulant addiction is a widespread problem in the United States that affects millions of individuals at a substantial cost in both lost wages and medical expenses. Amphetamines and cocaine act primarily by blocking monoamine reuptake facilitated by sodium- and chloride-dependent plasma membrane transporters for serotonin, norepinephrine and dopamine. Although these psychostimulants have equimolar affinity for the monoamine transporters, the reinforcing properties of these drugs are thought to be largely mediated by their interaction with the dopamine transporter (DAT). Recent in vitro and in vivo studies demonstrate that, in addition to inhibiting DAT function, amphetamines and cocaine also modulate DAT cell surface levels via membrane trafficking. Preliminary studies from our laboratory demonstrate that amphetamine- induced loss of cell surface DAT occurs via enhancing DAT internalization rates. However, it is unknown whether psychostimulant-induced changes in DAT surface expression are integral to the addictive process. This is due to a lack of available animal models to test this hypothesis. We recently identified a ten amino acid region spanning residues 587-596 in the DAT carboxy terminus that is necessary for basal and protein kinase C-stimulated DAT endocytosis. We propose to test whether psychostimulant- mediated DAT trafficking is required for the rewarding properties of psychostimulants. To this end, we aim to generate DAT "knock in" mice expressing endocytic-defective DATs. The resulting mice will be assessed for amphetamine self-administration, conditioned place preference and sensitization, to test whether DAT trafficking plays a role in the rewarding properties of psychostimulants. Moreover these animals will be an invaluable tool for future studies examining the role of DAT trafficking in synaptic transmission and dopaminergic plasticity. Psychostimulant abuse and addiction is a growing problem in the United States, reaching near epidemic proportions over the past several years. Despite numerous investigations into the mechanisms underlying psychostimulant addiction, there are still large gaps in our knowledge. The current proposal aims to develop an animal model in which the targets of amphetamine in the brain are modified, to determine whether the actions of amphetamine on these target proteins contribute to the addictive process.