Role of NMDAR Regulation in Phencyclidine-Induced Neurotoxicity

描述(由申请人提供)：苯环利定(PCP)是一种有效的解离麻醉剂，由于有报道称术后出现幻觉和定向障碍行为，临床应用被放弃。由于具有致幻作用，五氯苯酚在20世纪60年代中期出现在滥用毒品的场景中，S被称为“天使尘”，但由于它的拟精神特性，非法使用已大幅减少。人类对五氯苯酚的中毒也被证明模拟了精神分裂症的阳性和阴性症状，并加剧了精神分裂症患者的精神病。PCP的主要作用是作为一种非竞争性NMDAR拮抗剂，属于离子型谷氨酸受体家族的成员。在未成熟的大鼠中给予五氯苯酚已被证明能引起..神经毒性和后来发育中的异常行为。初步实验表明，两种不同的受体转运和蛋白质合成机制可能涉及围产期急性和亚慢性PCP给药之间存在的NMDAR上调的差异，这可能是PCP诱导的神经毒性机制的区域和剂量依赖差异的基础。本研究旨在探讨五氯苯酚对NMDAR的调节机制及其对围产期大鼠额叶皮质和纹状体神经毒性的影响。这个项目的具体目标将集中于描述NMDAR的调节机制，特别是通过使用合成和运输途径的选择性抑制剂和Western印迹分析，在急性和亚慢性给药后受体的合成和运输的作用。此外，我们计划利用~3H-MK-801结合来研究DA和5-羟色胺受体的间接激活在NMDAR中的作用。最后，为了将NMDAR的调节和功能与NMDA介导的细胞死亡联系起来，我们计划加入NR1和NR2A/B亚单位的双标记免疫组织化学以及已知的神经毒性标志裂解caspase-3。通俗易懂：五氯苯酚，又称“天使尘”，是一种强效的精神活性物质，主要在美国几个大城市的城市地区被滥用。它通过阻断负责记忆、情绪和高级思维过程的大脑区域的NMDA受体来引发自己的行动。本项目旨在进一步阐明PCP在NMDA受体上的作用，以深入了解其致幻、拟精神和神经毒性特性的机制。

DESCRIPTION (provided by applicant): Clinical use of phencyclidine (PCP), a potent dissociative anesthetic, was abandoned because of reports of post-operative hallucinations and disoriented behavior. Due to its hallucinogenic effects, PCP appeared on the drug of abuse scene in the mid-1960's known as "angel dust" but its illicit use has substantially diminished because of its psychotomimetic properties. PCP intoxication in humans has also been shown to mimic both the positive and negative symptoms of schizophrenia as well as exacerbate psychoses in schizophrenics. PCP elicits its major actions as a noncompetitive NMDAR antagonist, a member of the ionotropic glutamate family of receptors. PCP administration in immature rats has been shown to cause.. neurotoxicity and later in development, aberrant behaviors. Preliminary experiments have shown that two distinct mechanisms of receptor trafficking and protein synthesis are likely involved in the differences in NMDAR up-regulation that exist between perinatal acute and sub-chronic PCP administration and that this may underlie regional- and dosage-dependent differences in the mechanism of PCP-induced neurotoxicity. The purpose of this study is to determine the mechanism and functional consequences of PCP-induced regulation of the NMDAR in association with neurotoxicity in the frontal cortex and striatum in perinatal rats. The specific aims of this project will focus on delineating the mechanisms of regulation of the NMDAR, specifically the role of synthesis and trafficking of the receptor following acute and sub-chronic PCP administration through the use of selective inhibitors of synthesis and trafficking pathways and analysis via Western blot. In addition, we plan to investigate the role of indirect activation of DA and 5-HT receptors on the NMDAR using 3H-MK-801 binding. Finally, in order to relate regulation and function of the NMDAR to NMDA-mediated cell death, we plan to incorporate double-labeled immunohistochemistry of the NR1 and NR2A/B subunits and a known marker of neurotoxicity, cleaved caspase-3. Lay Summary: PCP, also known as "angel dust", is a powerful psychoactive substance that is mainly abused in urban regions of several large cities in the United States. It elicits its actions through blockade of the NMDA receptor in brain regions responsible for memory, emotions, and higher thought processes. This project aims to further clarify the actions of PCP at the NMDA receptor in order to gain insight into the mechanisms underlying its hallucinogenic, psychotomimetic, and neurotoxic properties.