MECHANOTRANSDUCTION IN BARORECEPTOR NEURONS AND DROSOPHILA SENSORY NEURONS

压力感受器神经元和果蝇感觉神经元的机械传导

• 批准号: 6564790
• 负责人: FRANCOIS M ABBOUD
• 金额: $ 23.33万
• 依托单位: UNIVERSITY OF IOWA
• 依托单位国家: 美国
• 财政年份: 2002
• 资助国家: 美国
• 起止时间: 2002-01-01 至 2002-12-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6564790
• 关键词: autonomic nervous system; baroreceptors; baroreflex; carotid sinus; electrophysiology; ion channel blocker; laboratory mouse; laboratory rat; membrane channels; receptor sensitivity; sodium channel; tissue /cell culture; transfection; voltage /patch clamp

The arterial baroreceptors are sensory endings restricted to the carotid sinus and aortic arch but with powerful regulatory influences. They transduce arterial pressure signals into neurohumoral regulation of cardiovascular structure and homeostasis. Despite a large amount of information on the determinants of activation of baroreceptor (BR) nerves, the molecular, cellular and functional determinants of mechanoelectrical transduction at their sensory nerve endings are largely unknown. Project IV of this PPG addresses the neurobiology of mechanosensation. This Project (IV.A.1) which was initiated four years ago, as focused on 1) the identification of BR neurons in the nodose ganglion; 2) culturing them in vitro; 3) the development of a quantitative system for their mechanical activation; and 4) the definition of their responses with measurements of whole cell membrane currents, single-channel openings [Ca2+]i. A functional correlate of the cellular mechanisms was sought by measurements of carotid sinus nerve activity in vivo. Based on very exciting preliminary studies, we now propose to test the hypothesis that the ENaC/degenerin family of proteins represent ionic channel responsible for mechanoelectrical transduction in BR neurons. This hypothesis gains a strong rationale from the discovery of a genetic link between touch sensation in C. Elegans and the evidence of mechanical activation of ENaC/degenerin channels. In preliminary studies we found that 1) the subunits of ENAC/degenerin, gamma ENaC; beta ENaC and BNC1 (recently cloned from brain), are expressed in the aortic arch adventitia in the nodose ganglia where the BR nerve terminals and BR neurons are located, respectively; 2) the activity of BNC1a (transfected into oocytes) is blocked by Gd3+, a known blocker of mechanosensory channels; and 3) the rise in [Ca2+]i in BR neurons during mechanical stimulation is blocked by amiloride, a known blocker of the ENaC/degenerin channels. Our aims are: first, to identify ENaC/degenerin ENaC/degenerin channels; and third, to attempt to disrupt the BR responses to mechanical stimulation at the cellular, organ and whole animal level by transfection of dominant- negatives of ENaC/degenerin family. The uniqueness of the project is in the joining of two leading laboratories, with expertise in neurobiology of autonomic control (Abboud) and in the molecular biology of ion channels (Welsh). With the added support of excellent cores in imaging, transgenic animals, and gene transfer, the promise of successful pursuit of this problem is ascertained.

动脉压力感受器是限制在颈动脉的感觉末端 鼻窦和主动脉弓，但具有强大的监管影响。他们 传递动脉压信号到神经肿瘤调节 心血管结构和稳态。尽管有大量 有关压力受体（BR）神经激活决定因素的信息， 机械电机的分子，细胞和功能决定因素 他们的感觉神经末端的转导在很大程度上是未知的。项目 该PPG的IV解决了机械敏化的神经生物学。这 四年前启动的项目（IV.A.1），重点是1） 鉴定淋巴神经节中BR神经元； 2）培养它们 体外3）开发用于机械的定量系统 激活; 4）通过测量的定义他们的响应定义 全细胞膜电流，单通道开口[Ca2+] i。一个 通过测量寻求细胞机制的功能相关性 体内颈动脉鼻窦神经活性。基于非常令人兴奋的 初步研究，我们现在提议检验 蛋白质的ENAC/Degenerin家族代表负责的离子通道 BR神经元中的机械电解转导。这个假设获得了 从触摸之间发现遗传联系的强大理由 秀丽隐杆线虫的感觉和机械激活的证据 ENAC/Degenerin通道。在初步研究中，我们发现1） ENAC/Degenerin的亚基，伽马ENAC； Beta ENAC和BNC1（最近 从大脑克隆），在主动脉弓床中表达 nodose神经节，BR神经终端和BR神经元位于 分别; 2）BNC1A的活性（转染到卵母细胞）为 由已知的机械感应通道的盖帽剂GD3+阻塞； 3） 在机械刺激期间，在BR神经元中的[Ca2+] i上升被阻止 Amiloride，ENAC/Degenerin通道的已知阻滞剂。我们的目标是： 首先，识别ENAC/Degenerin ENAC/Degenerin通道；第三，到 试图破坏BR对机械刺激的反应 细胞，器官和整个动物水平通过转染优势 ENAC/Degenerin家族的负面因素。 该项目的独特性在于两个领导 实验室，具有自主控制神经生物学专业知识（Abboud） 以及离子通道的分子生物学（威尔士）。与添加 在成像，转基因动物和基因中支持优秀的核心 转移，成功追求这个问题的承诺是 确定。