Cognitive effects of anesthetics and dopamine transport

说明（由申请人提供）：本赠款是为了回应 PA-96-026，“麻醉剂的分子药理学” 行动上”声明说（部分）。" . .很难 指定受影响的分子事件之间的直接相关性 麻醉剂和随后发生的生理效应。“在 初步数据部分，我们提出的证据分子之间的相互作用 挥发性麻醉剂和多巴胺转运蛋白（DAT）。我们的模型是： 最初，在表达和细胞质（DAT）之间存在正常运输。 在麻醉诱导时，一些麻醉剂直接与DAT结合，而一些麻醉剂直接与DAT结合。 激活蛋白激酶C（PKC），引起DAT的一些内化。 细胞外DA浓度增加，因为较少表达的DAT导致 DA的持续释放被反馈抑制， 在长时间的麻醉过程中， 细胞外DA被代谢，降低其浓度， 增加其代谢物的浓度。停止麻醉后， 麻醉剂首先从体内清除，使表达的DAT 函数和PKC返回到非活动状态。然后，DA浓度开始 恢复在系统几乎恢复后，DAT和细胞外DA 浓度恢复正常，但必须合成额外的DA， 补充新陈代谢所损失的能量。认知能力最终恢复正常 子系统恢复到基线值。我们建议用一个 一系列体外、大鼠、非人灵长类动物和人类研究，并确定 这些变化的生理意义，因为它们涉及认知 通过3个具体目标在人类中的性能：具体目标1：分析 细胞和亚细胞水平的DAT-麻醉剂相互作用。我们 假设DAT-麻醉剂相互作用在临床上是显著 某些麻醉剂的相关浓度，我们希望看到减少 麻醉剂给药后的[18F]FECNT结合和[3 H]多巴胺摄取 这是由于转运体的内化。具体目标2： 完整活组织中的DAT-麻醉剂相互作用。我们希望确认DAT 内化并观察细胞外DA的初始增加， DA减少和代谢物增加，这表明 DAT。与目标1相比，这些实验的结果将确定 与其他神经系统的互动是很重要的。他们还将提供一个 直接校准，用于解释目标3中的PET结果。具体目标3： 测量[18F]FECNT结合电位降低的持续时间， 与认知功能有关。使用 从目标1和2的结果，这个PET实验将提供有关DAT的信息 在人体麻醉后的表达。我们希望时间进程 结合潜力和认知表现的正常化， 好.

Description (provided by applicant): This grant is being submitted in response to the program announcement, PA-96-026, "Molecular Pharmacology of Anesthetic Action." The announcement states (in part) ." . .it has been difficult to assign a direct correlation between molecular events that are influenced by anesthetics and the physiological effects that subsequently occur." In the preliminary data section, we present evidence of molecular interaction between volatile anesthetics and the dopamine transporter (DAT). Our model is: Initially, there is normal trafficking between expressed and cytoplasmic (DAT). At induction of anesthesia, some anesthetic binds directly to the DAT and some activates protein kinase C (PKC) causing some internalization of DAT. The extracellular concentration of DA increases because fewer expressed DAT result in less reuptake of DA. Continued release of DA is inhibited by a feedback mechanism signaled from extracellular DA. During prolonged anesthesia, the extracellular DA is metabolized, which decreases its concentration while increasing the concentration of its metabolites. After cessation of anesthesia, the anesthetic first clears from the body allowing the expressed DAT to function and PKC to return to the inactive state. Then, DA concentration begins to recover. After the system has nearly recovered, the DAT and extracellular DA concentrations return to normal but additional DA must be synthesized to replenish that lost to metabolism. Cognitive ability normalizes after all subsystems return to baseline values. We propose to test this model with a series of in vitro, rat, non-human primate and human studies and to determine the physiological significance of these changes as they relate to cognitive performance in humans through 3 specific aims: Specific Aim 1: Analyze the DAT-anesthetic interaction at the cellular and sub-cellular level. We hypothesize that DAT-anesthetic interaction will be significant at clinically relevant concentrations for certain anesthetics and, we expect to see reduced [18F]FECNT binding and [3H]dopamine uptake following anesthetic administration due to trasnporter internalization. Specific Aim 2: Characterize the DAT-anesthetic interaction in intact living tissue. We expect to confirm DAT internalization and observe an initial increase in extracellular DA followed by decreased DA and increased metabolites indicating decreased functioning of the DAT. Results of these experiments in comparison with aim 1 will determine if interaction with other neural systems is important. They will also provide a direct calibration for interpreting the PET results in aim 3. Specific Aim 3: Measure the duration of decreased [18F]FECNT binding potential following anesthesia in humans and correlate with cognitive functioning. Using the results from aims 1 and 2, this PET experiment will give information about DAT expression in humans following anesthesia. We expect the time course to normalization of the binding potential and cognitive performance to correlate well.