The Role of Dopamine Transporter Trafficking in Psychostimulant Addiction

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，在工资损失和医疗费用方面都付出了巨大的代价。安非他明和可卡因主要通过阻断钠和氯依赖性质膜转运蛋白促进的单胺重摄取来发挥作用，这些转运蛋白用于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蛋白具有等摩尔亲和力，但这些药物的增强特性被认为主要是通过与多巴胺转运蛋白（DAT）的相互作用介导的。最近在体外和体内的研究表明，除了抑制DAT功能，安非他明和可卡因也通过膜运输调节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DAT的损失是通过提高DAT内化率发生的。然而，目前尚不清楚精神兴奋剂诱导的DAT表面表达的变化是否是成瘾过程的组成部分。这是由于缺乏可用的动物模型来测试这一假设。我们最近确定了一个10个氨基酸的区域，跨越残基587-596在DAT羧基末端，这是必要的基础和蛋白激酶C刺激的DAT内吞作用。我们建议测试是否精神兴奋剂介导的DAT贩运所需的奖励性质的精神兴奋剂。为此，我们的目标是产生DAT“敲入”表达内吞缺陷DAT的小鼠。将评估由此产生的小鼠的安非他明自我给药、条件性位置偏好和致敏性，以测试DAT贩运是否在精神兴奋剂的奖励性质中起作用。此外，这些动物将是一个宝贵的工具，为未来的研究中的作用，DAT贩运突触传递和多巴胺能可塑性。精神兴奋剂滥用和成瘾在美国是一个日益严重的问题，在过去几年中已接近流行病的程度。尽管对精神兴奋剂成瘾的潜在机制进行了大量的调查，但我们的知识仍然存在很大的差距。目前的提议旨在开发一种动物模型，其中安非他明在大脑中的靶点被修改，以确定安非他明对这些靶蛋白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.