Psychostimulants and Monoamine Transporters

描述（由申请人提供）：哌醋甲酯（MPD）和安非他明（AMPH）是被数百万人用于治疗注意缺陷多动障碍的滥用兴奋剂。我们的实验室最近发现了这些药剂以前未报告的影响。具体而言，MPD快速和可逆地增加囊泡多巴胺（DA）的摄取囊泡富集的亚细胞级分制备治疗大鼠。相比之下，AMPH类似物减少囊泡DA摄取在相同的馏分。这些影响发生的同时，增加和减少囊泡单胺转运蛋白-2（VMAT-2）的免疫反应后，MPD和AMPH类似物治疗，分别，并出现反映VMAT-2蛋白和/或囊泡内神经末梢的贩运。因此，本提案将测试的假设，MPD影响囊泡DA运输和神经元内定位的VMAT-2的方式不同于AMPH。这将通过以下方式实现： A.展示了MPD在VMAT-2定位上的独特功能，并将这些特性与AMPH的特性进行了比较。具体而言，我们将：i）鉴定与VMAT- 2的再分布相关的囊泡，以及VMAT-2在其中运输的亚细胞区室; ii）确定MPD诱导的VMAT-2再分布的区域选择性，以及这种变化是否是DA神经元特有的;以及iii）确定年龄和慢性治疗对MPD诱导的VMAT-2再分布的影响。 B。阐明MPD改变VMAT-2定位的机制。这将通过研究：i）D1和D2受体在VMAT-2再分布中的作用; ii）MPD对D2受体定位的急性作用; iii）突触蛋白在MPD诱导的VMAT-2分布变化中的作用来实现。 C.证明MPD对囊泡运输的作用的功能后果。具体来说，我们将研究：i）MPD改变囊泡DA隔离;和ii）MPD诱导的VMAT-2分布的改变是否对高剂量甲基苯丙胺给药引起的长期单胺能损伤具有神经保护作用。这些研究的完成将促进我们对MPD和AMPH的治疗效果，以及它们的滥用和不同的神经毒性责任的理解。这些数据也将提供深入了解的机制，调节囊泡DA的吸收和隔离。最后，这些研究将促进我们对各种过程的理解，包括那些潜在的成瘾和那些有助于DA神经退行性疾病发展的过程。

DESCRIPTION (provided by applicant): Methylphenidate (MPD) and amphetamine (AMPH) are stimulants of abuse that are used by millions for the treatment of attention deficit hyperactivity disorder. Our laboratory recently identified previously unreported effects of these agents. Specifically, MPD rapidly and reversibly increases vesicular dopamine (DA) uptake in a vesicle-enriched subcellular fraction prepared from treated rats. In contrast, AMPH analogs decrease vesicular DA uptake in the same fraction. These effects occur concurrent with increases and decreases in vesicular monoamine transporter-2 (VMAT-2) immunoreactivity after MPD and AMPH analog treatment, respectively, and appear to reflect trafficking of VMAT-2 protein and/or vesicles within nerve terminals. Accordingly, this proposal will test the hypothesis that MPD affects vesicular DA transport and the intraneuronal localization of VMAT-2 in a manner distinct from AMPH. This will be accomplished by: A. demonstrating the unique features of MPD on VMAT-2 localization, and comparing these properties with those of AMPH. Specifically, we will: i) identify the vesicles associated with the redistribution of VMAT- 2, and the subcellular compartments among which VMAT-2 are trafficking; ii) determine the regional selectivity of the MPD-induced redistribution of VMAT-2, and if this change is unique to DA neurons; and iii) determine the impact of age and chronic treatment on the MPD-induced redistribution of VMAT-2. B. elucidating mechanisms whereby MPD alters VMAT-2 localization. This will be accomplished by investigating: i) the role of D1 and D2 receptors in redistributing VMAT-2; ii) the acute effect of MPD on D2 receptor localization; and iii) the role of synapsin in the MPD-induced changes in VMAT-2 distribution. C. demonstrating functional consequences of the effect of MPD on vesicular trafficking. Specifically, we will investigate if: i) MPD alters vesicular DA sequestration; and ii) MPD-induced alterations in VMAT-2 distribution are neuroprotective against the long-term monoaminergic damage caused by high-dose methamphetamine administration. Completion of these studies will advance our understanding of the therapeutic effects of MPD and AMPH, as well as their abuse and dissimilar neurotoxic liabilities. These data will also provide insight into mechanisms underlying the regulation of vesicular DA uptake and sequestration. Finally, these studies will advance our understanding of a wide array of processes including those underlying addiction and those contributing to the development of DA neurodegenerative diseases.