The Role of Dopamine Transporter Trafficking in Psychostimulant Addiction

描述(由申请人提供)：精神刺激成瘾在美国是一个普遍存在的问题，影响着数以百万计的人，在工资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依赖钠和氯的质膜转运体促进的单胺再摄取来发挥作用。虽然这些精神刺激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在很大程度上是通过它们与多巴胺转运体(DAT)的相互作用来调节的。最近的体外和体内研究表明，除了抑制DAT功能外，苯丙胺和可卡因还通过膜转运调节DAT细胞表面的水平。我们实验室的初步研究表明，苯丙胺诱导的细胞表面DAT的丢失是通过增加DAT的内化率而发生的。然而，尚不清楚心理刺激剂诱导的DAT表面表达的变化是否是成瘾过程中不可或缺的。这是因为缺乏可用的动物模型来检验这一假说。我们最近在DAT的羧基末端发现了一个跨越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内吞所必需的。我们建议测试心理刺激剂介导的DAT交易是否需要心理刺激剂的奖赏特性。为此，我们的目标是培育出表达内吞缺陷DAT的DAT“敲入”小鼠。由此产生的小鼠将接受苯丙胺自我给药、条件性位置偏爱和敏感化的评估，以测试DAT贩运是否在精神刺激剂的奖赏特性中发挥作用。此外，这些动物将是未来研究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。精神刺激性药物的滥用和上瘾在美国是一个日益严重的问题，在过去几年里几乎达到了流行的程度。尽管对精神刺激性成瘾的潜在机制进行了大量研究，但我们的知识仍然存在很大差距。目前的提议旨在开发一种动物模型，在该模型中，大脑中的苯丙胺靶标被修饰，以确定苯丙胺对这些靶标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.