经典瞬时受体（TRPC）通道——缺氧激活外周化学感受器的新靶点

A great deal of data from clinic patients and experimental animals has shown that the enhanced peripherial chemereceptor reflex induces the increased sympathetic nerve activity, then exacerbates the progression of heart failure. Rencently,it is challeged that the L-type calcium is the only channel to involve in activation of peripheral chemoreceptor by hypoxia. This project will explore the role of transient receptor potential canonical(TRPC) channel in hypoxia-activated carotid chemoreceptor activity.We will measure calcium influx by calcium image and TRPC channel function by patch clamp to screen which subtype of TRPC is senstive to hypoxia.The molecular mechanism will be demonatrated in the culture cell with TRPC overexpression or knock down by gene transfection with plasmid, adenovirus or siRNA techaniques. The role of oxygen-sensitive-TRPC subtypes in carotid chemorector activity will be evaluated in isolated carotid chemoreceptor preparation and in vivo chemoreflex activity. Further experiments will be performed in ischemic heart failure model to explore whether oxygen-sensitve-TRPC sutypes contributes to the enhanced periphearal chemorecheart activation under heart failure condition. Those results will imply new experimental evidence and approach to prevent and treat heart failure diseases.

临床资料和大量动物实验结果表明，心力衰竭状态下增强的外周化学感受器反射所致的高兴奋交感神经活动，参与并加速心衰的进程。新近的资料显示电压依赖性钙离子通道并不是唯一参与缺氧刺激外周化学性感受器的唯一通道，所以本项目主要探讨经典的瞬时受体电位 (TRPC）通道介导的钙内流在缺氧所致化学感受器兴奋中的作用。将采用包括质粒，腺病毒和siRNA 等转染方法表达和抑制相应的TRPC 亚型，通过细胞钙内流成像和膜片钳技术在培养细胞筛选和确定缺氧所激活的TRPC通道亚型，并探讨缺氧激活TRPC的分子机制； 也将采用游离的颈动脉体化学感受器活动，在体的外周化学感受器反射的手段，系统评价这些缺氧敏感性TRPC 亚型在缺氧所致的颈动脉化学感受器激活的作用。在缺血所致的心衰模型上，进一步揭示缺氧敏感性TRPC通道在心力衰竭病理状态下所致异常外周化学感受器活动的作用，为心力衰竭疾病防治提供新的实验依据和思路。