Transporter Mechanism of Amphetamine Sensitization

描述(由申请人提供)：该提案将首次描述和理解苯丙胺(AMPH)诱导的多巴胺转运体(DAT)和5-羟色胺转运体(SERT)在AMPH致敏小鼠中的贩运。在人类和实验动物中反复出现AMPH会导致行为和神经化学敏化，这可能是药物诱因突出的基础，例如“想要药物”。了解药物对致敏动物的影响具有重要的临床意义，因为人类吸毒者通常已经对药物敏感，会反复服药。由于Amph通过与表面DAT结合发挥作用，DAT转运对于DAT底物(Amph和多巴胺)的作用强度和持续时间很重要。DAT转运主要由DAT底物(如AMPH)和D2R激动剂(如奎比罗)诱导。Amph也是SERT的底物，SERT在Amph强化和增敏中起重要作用。丝氨酸的贩运受底物的调节。Amph重复诱导的DAT和SERT转运的改变将影响多巴胺和5-羟色胺能信号，这可能是Amph敏化或耐受的细胞机制之一。这项建议将在我目前非NIH资助的拨款的基础上扩展，以分析三个具体目标：1)表征amph和喹比罗诱导的amph致敏小鼠与生理盐水处理的小鼠的DAT内化和再循环，并确定PKC2是否发挥作用；2)确定重复amph是否会改变SERT的运输和增加5羟色胺的外流，以及PKC2是否发挥作用；以及3)确定重复amph是否改变与DAT和SERT关联的Synaxin 1A。这将是第一次研究在AMPH致敏状态下啮齿动物体内DAT和SERT的运输，并可能揭示人类在药物暴露和戒断过程中药物反应的不同阶段。这项研究具有广泛的应用前景，因为DAT和/或SERT与许多其他神经精神疾病有关，如精神分裂症、双相情感障碍和抑郁症，这些疾病通常与药物滥用共存。1 公共卫生相关性：人类对药物的渴求和滥用是通过反复苯丙胺治疗引起的啮齿类动物的苯丙胺敏化来模拟的。了解苯丙胺敏化动物模型中多巴胺转运体和5-羟色胺转运体的转运情况，将为药物敏化状态下的多巴胺和5-羟色胺能信号传导提供相关信息，并为药物干预提供新的细胞途径。在多巴胺和5-羟色胺交易中发现的变化也将与精神分裂症、双相情感障碍和抑郁症有关，这些疾病通常与药物滥用并存。

DESCRIPTION (provided by applicant): This proposal will provide for the first time characterization and understanding of amphetamine (AMPH)- induced dopamine transporter (DAT) and serotonin transporter (SERT) trafficking in the AMPH sensitized mouse. Repeated AMPH in humans and laboratory animals leads to a behavioral and neurochemical sensitization which may underlie the incentive salience of drugs, e.g., "drug wanting". Understanding the effect of drugs on a sensitized animal is of significant clinical relevance given that human drug addicts, often already sensitized to drugs, repeatedly take drugs. Since AMPH exerts its effect by binding to surface DAT, DAT trafficking is important for the strength and duration of DAT substrate (AMPH and dopamine) action. DAT trafficking is primarily induced by DAT substrate (e.g. AMPH) and D2R agonist (e.g. quinpirole). AMPH is also a substrate for SERT, and SERT is importantly involved in AMPH reinforcement and sensitization. SERT trafficking is regulated by substrates. An alteration in repeated AMPH-induced DAT and SERT trafficking will affect dopaminergic and serotonergic signaling, which may contribute to the cellular mechanisms of AMPH sensitization or tolerance upon repeated AMPH exposure. This proposal will expand upon my present non-NIH funded grant to analyze three specific aims: 1) characterize AMPH- and quinpirole-induced DAT internalization and recycling in AMPH sensitized vs. saline- treated mice and determine whether PKC2 plays a role; 2) determine if repeated AMPH will alter SERT trafficking and enhance serotonin efflux, and whether or not PKC2 plays a role; and 3) determine if repeated AMPH alters syntaxin 1A association with DAT and SERT. This will be the first study to investigate DAT and SERT trafficking in AMPH sensitized state in rodents, and may shed light on different phases of drug responses in humans upon drug exposure and during withdrawal. This study has a broad application because DAT and/or SERT are implicated in many other neuropsychiatric diseases such as schizophrenia, bipolar disorder and depression, which are commonly comorbid with drug abuse. 1 PUBLIC HEALTH RELEVANCE: Human drug craving and abuse is modeled by amphetamine sensitization in rodents induced by repeated amphetamine treatment. Understanding the trafficking of dopamine transporter and serotonin transporter in the animal model of amphetamine sensitization will provide pertinent information about the dopaminergic and serotonergic signaling in the state of drug sensitization in drug addicts, and provide a new cellular avenue for potential drug intervention. The changes found in dopamine and serotonin trafficking will also be relevant to schizophrenia bipolar disorder and depression, which are often comorbid with substance abuse.