MODULATION OF THE ACTION OF PCP BY MG2+ AND POLYAMINES

苯环利定（PCP）在大脑中的主要作用部位是N- 谷氨酸受体的甲基-D-天冬氨酸（NMDA）亚型。五氯苯酚与 NMDA受体受Mg 2+和多胺调节。不过虽然 多胺和Mg~（2+）对蛋白质结合有显著的调节作用。 PCP，这些调节剂改变受体的位点和机制 功能了解不多。本研究的长期目标是 为了理解这些调节剂的作用机制， PCP的NMDA受体，并使用这些调制器网站作为目标 用于改变或阻断PCP药理作用的药物。我们 将采用三种融合的方法，使用合成化学， 分子生物学和药理学来实现这一目标。具体目标 该项目的主要内容是： 1.寻求多胺拮抗剂的合理设计与合成。使用 以青蒿素为先导化合物， 和疏水性的新型双胍，我们将开发多胺 拮抗剂比目前的药物更有效和/或更具选择性， 可用的药物。 2.对新型多胺配体进行了表征。我们将使用 配体结合试验和细胞内Ca2+试验，以确定 新合成的多胺位点药物的活性和特异性。我们 还将确定PCP行动可以通过以下方式修改的程度： 多胺拮抗剂 3.确定多胺激动剂和拮抗剂对配体的影响， 与哺乳动物中表达的重组NMDA受体亚单位的结合 细胞我们将评估多胺对确定的NMDA受体亚单位的作用 组合，它提供了一个更具体的方法来调查 该调节剂对NMDA受体复合物的作用机制。 4.为了确定升高的细胞内游离Mg 2+对 通过PCP位点配体抑制NMDA受体。我们将使用Ca2 +- 依赖性和Ca2+非依赖性的方法来升高细胞内[Mg2 +]， 测试假设，升高[Mg2 +]将减少PCP结合到 NMDA受体。 了解Mg2+和多胺的分子机制 影响五氯苯酚的作用将提供重要的新信息， 这种重要的滥用物质的分子作用机制。 该项目还将侧重于预防影响的战略 PCP对NMDA受体的作用，从而为PCP提供了治疗靶点 五氯酚滥用的治疗

The principal site of action of phencyclidine (PCP) in the brain is the N- methyl-D-aspartate (NMDA) subtype of glutamate receptor. PCP binding to the NMDA receptor is modulated by Mg2+ and polyamines. However, although polyamines and Mg2+ have substantial modulatory effects on the binding of PCP, the sites and mechanisms by which these modulators alter receptor function is poorly understood. The long term goal of the present study is to understand the mechanism of action of these modulators one the binding of PCP to the NMDA receptor, and to use these modulator sites as targets for drugs that will alter or block the pharmacological effects of PCP. We will take three convergent approaches, using synthetic chemistry, molecular biology and pharmacology to achieve this goal. The specific aims of this project are: 1. To pursue rational design and synthesis of polyamine antagonists. Using arcaine as a lead compound and systematically modifying size, conformation and hydrophobicity of novel bisguanidines we will develop polyamine antagonists that are more potent and/or more selective than the currently available drugs. 2. To pharmacologically characterize novel polyamine ligands. We will use ligand binding assays and intracellular Ca2+ assays to establish the activity and specificity of newly synthesized polyamine site drugs. We will also determine the extent to which PCP action can be modified by polyamine antagonists. 3. To determine the effect of polyamine agonists and antagonists on ligand binding to recombinant NMDA receptor subunits expressed in mammalian cells. We will assess polyamine action on defined NMDA receptor subunit combinations, which offers a more specific approach to investigating the mechanism of action of this modulator on the NMDA receptor complex. 4. To determine the effects of elevated intracellular free Mg2+ on inhibition of NMDA receptors by PCP site ligands. We will use Ca2+- dependent and Ca2+-independent methods to elevate intracellular [Mg2+] to test the hypothesis that elevated [Mg2+] will decrease PCP binding to the NMDA receptor. Understanding the molecular mechanisms by which Mg2+ and polyamines influence the actions of PCP will provide important new information about the molecular mechanisms of action of this important substance of abuse. This project will also focus on strategies that will prevent the effects of PCP on the NMDA receptor, and thereby offer a therapeutic target for the treatment of PCP abuse.