Ion Channels in Mechanosensitive Neurons

描述（由申请人提供）：该项目的长期目标是了解机械感觉信息的产生和传递，从压力感受器感觉终端到孤立束核的中央终端。这是一项更广泛的研究工作的一部分，旨在确定动脉压和心律的神经调节的神经生理学和神经解剖学基础。在这项拨款中，我们正在研究一种新的离子通道家族的分布和功能，即钙渗透阳离子通道的TRPC家族。这些通道很重要，因为它们是钙内流的来源，通过影响膜电位、中枢末端的递质释放和外周末端的感觉放电来调节神经元活动的模式。有四个具体目的：第一个是检查压力感受器传入纤维中TRPC通道的分布。利用免疫组织化学，我们将在三个区域确定压力感受器传入通路中TRPC通道的位置：主动脉弓内有髓鞘纤维和无髓鞘纤维的外周感觉受体，结节神经节内的胞体和孤立束核内的突触终端。在第二个目标中，我们将询问是什么配体激活了这些通道，使用细胞附着斑块中的通道电生理特征和穿孔斑块全细胞记录中的全细胞电流。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评估相对于电压门控通道的TRPC通道的贡献，从而探索激活机制。最后，在目标四中，我们探讨了激活特定TRPC通道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.