Canonical Transient Receptor Potential Channels and Excitotoxicity

（修订摘要） 兴奋性毒性在癫痫、中风和头部的病理生理学中起着中心作用 外伤谷氨酸受体的过度激活导致钙超载，触发 神经元细胞死亡然而，开发离子型谷氨酸受体的努力， 拮抗剂作为神经保护剂尚未成功;替代的分子 需要确定开发神经保护化合物的靶点。代谢型 谷氨酸受体（mGluR）是G蛋白偶联的谷氨酸受体家族。 第一组mGluR（mGluR 1和mGluR 5）与癫痫发作有关， 兴奋性毒性然而，由I组介导的兴奋性毒性的潜在机制 mGluRs未知。本申请的主要假设是I组mGluRs 通过激活经典瞬时受体而导致癫痫发作和兴奋性毒性 潜在的（TRPC）通道，这是一个亚组的TRP超家族的非选择性 阳离子通道TRPC通道被认为是钙库操纵的钙通道（SOC） 并且还被与磷脂酶C偶联的G蛋白偶联受体激活， 作为I组mGluRs。我们的初步数据表明，TRPC 1/4/5亚组 TRPC由I组mGluRs激活，在平台电位中起关键作用 I组mGluR激动剂诱导的癫痫样爆发性放电的基础 隔膜，边缘系统结构非常容易受到癫痫引起的兴奋性毒性。遵循 在这一初步发现的基础上，本研究的具体目标1将研究这一平台期是否 用TRPC通道阻断剂消除TRPC通道可消除这种电位 以及通过使用针对特定TRPC通道的基因敲除方法。具体目标1 还将确定mGluR介导的平台期与 侧隔潜在和急性兴奋性毒性。为了确定TRPC是否 通道有助于癫痫发作和兴奋性毒性在体内，公认的毛果芸香碱- 将使用诱导的边缘癫痫发作模型。具体目标2将检验以下假设： TRPC 1和TRPC 4在体内参与匹罗卡品诱导癫痫发作的易感性; 和具体目标3将确定TRPC 1和TRPC 4的不同作用， 在体内由匹鲁卡品诱导的癫痫发作引起的神经变性。的长期目标 本项目旨在阐明TRPC家族不同成员的具体作用， 兴奋性毒性 （摘要修订说明） 对摘要所做的修改包括删除所有提到的实验 涉及TRPC 5（-/-）或TRPC 1（-/-）/TRPC 5（-/-）敲除小鼠的使用。在 此外，摘要中提到的信号研究已被删除。其他一切都 保持不变，因为拟议的实验仍然在赠款地址， 原补助金范围。

(revised abstract) Excitotoxicity plays a central role in the pathophysiology of epilepsy, stroke and head trauma. Overactivation of glutamate receptors leads to calcium overloading, triggering neuronal cell death. However, efforts to develop ionotropic glutamate receptor antagonists as neuroprotective agents have yet to be successful; alternative molecular targets for developing neuroprotective compounds need to be identified. Metabotropic glutamate receptors (mGluRs) are a family of G-protein coupled glutamate receptors. Group I mGluRs (mGluR1 and mGluR5) have been implicated in seizures and excitotoxicity. However, the underlying mechanism of excitotoxicity mediated by group I mGluRs is not known. The main hypothesis of this application is that group I mGluRs contribute to seizure and excitotoxicity by activating the canonical transient receptor potential (TRPC) channels, which is a subgroup of the TRP superfamily of non-selective cation channels. TRPC channels are identified as store-operated calcium channels (SOC) and are also activated by G-protein coupled receptors coupled to phospholipase C, such as group I mGluRs. Our preliminary data suggest that the TRPC1/4/5 subgroup of TRPCs, activated by group I mGluRs, play a critical role in the plateau potential underlying the epileptiform burst firing induced by group I mGluR agonists in the lateral septum, a limbic structure highly vulnerable to seizure-induced excitotoxicity. To follow up on this initial finding, Specific Aim 1 of this study will examine whether this plateau potential can be abolished by eliminating TRPC channels with TRPC channel blockers and by using a genetic knockout approach for specific TRPC channels. Specific Aim 1 will also determine whether there is a causal link between the mGluR-mediated plateau potential and acute excitotoxicity in the lateral septum. To determine whether TRPC channels contribute to seizure and excitotoxicity in vivo, the well-established pilocarpine- induced limbic seizure model will be used. Specific Aim 2 will test the hypothesis that TRPC1 and TRPC4 contribute to susceptibility to pilocarpine-induced seizures in vivo; and Specific Aim 3 will determine the distinct roles of TRPC1 and TRPC4 in neurodegeneration caused by pilocarpine-induced seizures in vivo. The long-term goal of this project is to elucidate the specific role of distinct TRPC family members in excitotoxicity. (description of abstract revision) The changes made to the abstract involve a deletion of all mention of experiments dealing with the use of the TRPC5(-/-) or TRPC1(-/-)/TRPC5(-/-) knockout mice. In addition, the signaling studies mentioned in the abstract have been deleted. All else has remained the same since the proposed experiments to remain in the grant address the original scope of the grant.