PERSISTENT COCAINE INDUCED CHANGES IN DOPAMINE CLEARANCE

描述：（申请人摘要） 此申请是一个独立的持续资金的请求 科学家奖（伊萨; K 02），以支持该部门的Nancy Zahniser博士 科罗拉多大学医学院药理学博士。 的重要性 Zahniser博士的职业生涯和专业成长是，它将 继续（1）尽量减少她的行政和教学责任， (2)加强她对药物滥用研究的关注，（3）让她致力于 最大的努力，对新的研究方向开始在以前的 支持期和（4）提供更多的机会，以进一步延长 她的研究范围。 在过去的四年里。 Zahniser博士的实验室 开发并表征了一种体内电化学方法， 外源性多巴胺（DA）清除率，DA转运蛋白（DAT）的测量 活动，在麻醉大鼠的离散脑区。 使用此 方法，他们证明，与行为敏化一致， 可卡因抑制DA清除的能力持续增强， 退出后，尾壳核，而不是尾壳核， 反复服用可卡因。 对中提出的实验至关重要 在本申请中，她和她的合作者最近扩展了 这种方法可以测量行为和DAT活动， 同时在自由移动的大鼠中。 在一个合作项目中， 在Zahniser博士的休假期间，在爪蟾卵母细胞中表达的人类DAT被 显示为产电的，具有某些离子通道样特性， 是电压依赖的。 这里提出的实验将探索后者 在卵母细胞表达系统和脑切片中进一步发现， 大鼠和D2 DA受体敲除小鼠。 具体而言，建议 实验将检验以下假设：（I） 外源性DA从细胞外间隙清除的速率与 内源性DA清除，（2）DAT活性的持续变化， 特定的大脑区域有助于可卡因诱导的 行为敏化和（3）D2 DA自身受体诱导的变化， 膜电位瞬时调节DAT活性。 的结果予以 这些研究不仅将加深对大脑持续变化的理解， DA 有助于行为敏感化的系统， DAT活性受到瞬时调节。

DESCRIPTION: (Applicant's Abstract) This application is a request for continued funding of an Independent Scientist Award (ISA; K02) to support Dr. Nancy Zahniser in the Department of Pharmacology, University of Colorado School of Medicine. The importance of this ISA to Dr. Zahniser's career and professional growth is that it will continue to (1) minimize her administrative and teaching responsibilities, (2) enhance her focus on drug abuse research, (3) allow her to devote maximal effort toward new research directions initiated during the previous support period and (4) provide increased opportunities to further extend the scope of her research. During the past four years. Dr. Zahniser's lab developed and characterized an in vivo electrochemical method to measure exogenous dopamine (DA) clearance, a measure of DA transporter (DAT) activity, in discrete brain regions of anesthetized rats. Using this approach, they demonstrated that, consistent with behavioral sensitization, the ability of cocaine to inhibit DA clearance is persistently enhanced in nucleus accumbens, but not caudate-putamen, following withdrawal from repeated cocaine administration. Critical to the experiments proposed in the present application, she and her collaborators have recently extended this methodology so that behavior and DAT activity can be measured concurrently in freely-moving rats. In a collaborative project initiated during Dr. Zahniser's sabbatical, human DAT expressed in Xenopus oocytes was shown to be electrogenic, to possess some ion channel-like properties and to be voltage-dependent. Experiments proposed here will explore the latter finding further in the oocyte expression system and in brain slices from rats and D2 DA receptor knockout mice. Specifically, the proposed experiments will test the following hypotheses: (I) that the rate at which exogenous DA is cleared from the extracellular space parallels the rate of endogenous DA clearance, (2) that persistent changes in DAT activity in specific brain regions contribute to the expression of cocaine-induced behavioral sensitization and (3) that D2 DA autoreceptor-induced changes in membrane potential transiently regulate DAT activity. The results of these studies will enhance understanding not only of persistent changes in brain DA systems that contribute to behavioral sensitization but also of mechanisms by which DAT activity is transiently regulated.