Ion Channels in Mechanosensitive Neurons

描述（由申请人提供）：本项目的长期目标是了解机械感觉信息从压力感受器感觉末梢到其在孤束核中的中央终止的产生和传递。这是一个更广泛的研究努力，以确定神经生理学和神经解剖学的基础，动脉压和心脏节律的神经调节的一部分。在这项资助中，我们正在研究一个新的离子通道家族的分布和功能，TRPC家族的钙渗透性阳离子通道。这些通道是重要的，因为它们作为钙内流的来源，预期钙内流通过对膜电位、中枢末端的递质释放和外周末端的感觉放电的影响来调节神经元活动的模式。有四个具体的目标：第一个检查TRPC通道的压力感受器传入纤维中的分布。使用免疫组织化学，我们将定义TRPC通道的位置在压力感受器传入通路中的三个区域：外周感觉受体的有髓和无髓纤维在弓的主动脉，在他们的索马在结状神经节和他们的突触末梢在孤束核。在第二个目标中，我们将问什么配体激活这些通道，使用电生理学表征的通道在细胞附着的补丁和全细胞电流穿孔补丁全细胞记录。在第三个目标中，我们通过使用钙成像技术检查激动剂对钙内流的影响来研究激活机制，以评估TRPC通道相对于电压门控通道的贡献。最后，在第四个目标中，我们探讨了特定TRPC通道激活在全细胞电压记录中的功能后果。这些研究将包括RNA干扰以消除特定通道。

DESCRIPTION (provided by applicant): The long-term objective of this project is to understand the generation and transmission of mechanosensory information from the baroreceptor sensory terminal to its central termination in the nucleus of the solitary tract. This is part of a broader research effort to determine the neurophysiological and neuroanatomical substrate that underlies neural regulation of arterial pressure and cardiac rhythm. In this grant we are examining the distribution and the function of a new family of ion channels, the TRPC family of calcium permeable cation channels. These channels are important because they serve as a source of calcium influx that is expected to modulate the pattern of neuronal activity through effects on membrane potential, transmitter release at the central terminals and sensory discharge at the peripheral terminals. There are four specific aims: the first examines the distribution of the TRPC channels in the baroreceptor afferent fibers. Using immunohistochemistry, we will define the location of TRPC channels in the baroreceptor afferent pathway in three regions: the peripheral sensory receptors of myelinated and unmyelinated fibers in the arch of the aorta, in their soma in the nodose ganglion and in their synaptic terminals in the nucleus of the solitary tract. In the second aim we will ask what ligands activate these channels using an electrophysiological characterization of the channels in cell-attached patches and whole cell current in perforated patch whole cell recording. In the third aim we pursue the mechanism of activation by examining the effect of agonist on calcium influx using calcium imaging techniques to evaluate the contribution of the TRPC channels relative to the voltage-gated channels. Finally, in aim four we explore the functional consequence of activation of specific TRPC channels in whole cell voltage recording. These studies will include RNA interference to eliminate specific channels.