Targeted regulation of CGRP activity in trigeminovascula

这些研究的主要目的是检查三叉神经血管系统中降钙素基因4“相关肽（CGRP）活性的分子控制。来自三叉神经节神经元的CGRP是脑循环中最有效的血管扩张机制之一。CGRP在蛛网膜下腔出血、高血压和偏头痛中的作用突出了其重要性。我们最近的研究表明，病毒递送CGRP能够预防蛛网膜下腔出血后的血管痉挛。为了了解CGRP的作用机制，我们建议对CGRP受体的调控亚基进行研究。三叉神经节神经元和脑血管上的突触前受体和突触后受体均有报道。然而，定义CGRP受体活性的分子机制直到最近才为人所知。CGRP受体是降钙素受体样受体（CRLR）和两个调节亚基（受体活性修饰蛋白1 （RAMP1）和受体成分蛋白（RCP））的三聚体。

The major goal of these studies is to examine the molecular control of calcitonin gene4"elated peptide (CGRP) activity in the trigeminovascular system. CGRP from trigeminal ganglia neurons is one of the most potent vasodilator mechanisms in the cercbral circulation. The importance of CGRP is highlighted by its involvement in subarachnoid hemorrhage, hypertension, and migraine. We have recently shown that viral delivery of CGRP is capable of preventing vasospasm after subarachnoid hemorrhage. To understand the mechanisms of CGRP action, we now propose to study the CGRP receptor regulatory subunits. Both presynaptic and postsynaptic receptors on the trigeminal ganglia neurons and cerebral vessels have been reported. However, the molecular mechanisms that define CGRP receptor activity are only recently becoming known. The CGRP receptor is a trimer of the calcitonin receptor-like receptor (CRLR) and two regulatory subunits called receptor activity-modifying protein 1 (RAMP1) and receptor component protein (RCP). RAMP1 is required for ligand binding activity and RCP is required for full signaling activity. We propose to test the hypothesis that gene transfer of CGRP receptor subunits can increase CGRP activity in the trigeminovascular system. Specifically, we will ask whether the RAMP1 and RCP proteins can regulate presynaptic and postsynaptic CGRP receptor function in trigeminal ganglia neurons and vascular muscle. The approach will be to use primary cell cultures and transgenic mice. First, the CGRP receptor proteins will be tested in cultured trigeminal neurons and vascular muscle. Second, CGRP-induced vasorelaxation will be measured in vitro using large arteries from RAMP1 and RCP transgenic mice and vasomotor responses will be studied in cerebral microvessels in vivo. Third, relaxation of the basilar artery will be compared in wildtype and transgenic mice in combination with CGRP gene transfer. This project builds on and continues our past studies on effects of CGRP and CGRP gene transfer in the cerebrovasculature. By coupling receptor studies with our adenoviral vector encoding CGRP we expect to lay the foundation for a combined approach of CGRP gene delivery and CGRP receptor modulation. The project will bring together expertise in cerebral circulation (Faraci and Heistad), CGRP expression (Russo), and CGRP receptor function (Dickerson). The significance of this project is that it will provide a new understanding of mechanisms of CGRP action and a potentially new perspective on therapeutic strategies for vascular disorders.