PHARMACOLOGY OF DOPAMINE RELEASE BY AMPHETAMINE

安非他明释放多巴胺的药理学

• 批准号: 6132577
• 负责人: MARGARET E GNEGY
• 金额: $ 25.35万
• 依托单位: UNIVERSITY OF MICHIGAN AT ANN ARBOR
• 依托单位国家: 美国
• 财政年份: 2000
• 资助国家: 美国
• 起止时间: 2000-08-01 至 2004-04-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6132577
• 关键词: amphetamines; calcium; dopamine; dopamine agonists; dopamine transporter; enzyme activity; isozymes; laboratory rat; neuropharmacology; phosphorylation; protein kinase C; synaptosomes; transfection

DESCRIPTION:(Applicant's Abstract) Knowledge of factors that regulate the plasmalemma dopamine transporter (DAT) is crucial to a complete understanding of the actions of several drugs of abuse. The motor stimulant and reinforcing effects of amphetamine (AMPH) and methamphetamine (METH), substrates of DAT, are due to their ability to increase the release of dopamine (DA). AMPHs appear to elicit reverse transport through DAT by an exchange diffusion mechanism. Our data reveal an unexpected component in AMPH-mediated reverse transport of DA. We find that AMPH-mediated outward transport of DA requires protein kinase C (PKC) activity and intracellular Ca2+. Direct PKC activation mimics the releasing activity of AMPH. The substrate for the PKC phosphorylation could be the DA transporter itself since both AMPH and PKC activators elicit phosphorylation of DAT. The focus of this proposal is to elucidate the mechanism by which PKC exerts its effects on DA outward transport. The hypothesis to be tested is that AMPH transport activates PKC which elicits a phosphorylation of DAT that, in turn, enhances outward transport. The specific aims are: 1. Determine whether DAT agonists other than AMPH increase the phosphorylation of DAT. 2. Test the hypothesis that an AMPH-mediated phosphorylation of DAT is responsible for enhanced AMPH-mediated DA release. 3. Determine whether TPA and the AMPH-induced increase in phosphorylation alter insertion of DAT into the membranes of rat synaptosomes and of hDAT-transfected cos-7 cells. 4. Test the hypothesis that AMPH increases PKC activity by increasing translocation of a PKC isozyme proximal to DAT. Smokable forms of METH are becoming more popular in America, signalling the start of a new wave of AMPH abuse. Since AMPH is a substrate for DAT, its mechanism of action is different from that of cocaine, an antagonist. AMPH does not act at a classical receptor, and the DAT antagonist, cocaine, is also widely abused. Thus, an ideal inhibitor of AMPH would block its ability to release DA. A more complete understanding of the mechanism of AMPH action can lead to a more rational design of inhibitors of the amphetamines.

描述：(申请人摘要) 对调节质膜多巴胺转运体(DAT)的因素的认识 对于全面了解几种药物的作用至关重要。 虐待。安非他明和安非他明的运动刺激性和增强作用 甲基苯丙胺(甲基苯丙胺)是DAT的底物，由于它们有能力增加 多巴胺(DA)的释放。AMPH似乎通过诱导反向运输 DAT通过交换扩散机制实现。我们的数据揭示了一个意想不到的成分 在Amph介导的DA的反向转运中。我们发现AMPH介导的外向 DA的转运需要蛋白激酶C(PKC)的活性和细胞内 Ca2+。PKC的直接激活模拟AMPH的释放活性。这个 PKC磷酸化的底物可能是DA转运体本身，因为 AMPH和PKC激活剂均可诱导DAT的磷酸化。这件事的重点是 建议阐明PKC对DA发挥作用的机制 向外运输。需要检验的假设是amph转运激活了 PKC引起DAT的磷酸化，进而增强向外 运输。具体目标是： 1.确定除AMPH外的DAT激动剂是否增加了磷酸化 DAT。 2.检验Amph介导的DAT磷酸化是 负责增强Amph介导的DA释放。 3.确定TPA和AMPH诱导的磷酸化增加是否改变 DAT插入大鼠突触体膜及转HDAT基因的研究 COS-7细胞。 4.验证AMPH通过提高PKC活性 DAT近端的PKC同工酶易位。 可吸烟形式的冰毒在美国变得越来越流行，这表明 开始了新一波的安非他命虐待。由于Amph是DAT的底物，其 作用机制与可卡因不同，可卡因是一种拮抗剂。Amph做了 不作用于经典的受体，DAT拮抗剂可卡因也是 被广泛滥用。因此，一种理想的Amph抑制剂将阻断其作用 释放检察官。对amph作用机制的更完整的理解可以 从而使苯丙胺类药物的抑制剂设计更加合理。