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: 6272497
• 负责人: FRANCOIS M ABBOUD
• 金额: $ 18.15万
• 依托单位: UNIVERSITY OF IOWA
• 依托单位国家: 美国
• 财政年份: 1998
• 资助国家: 美国
• 起止时间: 1998-03-06 至 1998-12-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6272497
• 关键词: autonomic nervous system; baroreceptors; baroreflex; carotid sinus; electrophysiology; 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.

动脉压力感受器是仅限于颈动脉的感觉末梢 窦和主动脉弓，但具有强大的调节影响。他们 将动脉压信号转变成神经体液调节 心血管结构和体内平衡。尽管有大量 有关压力感受器 (BR) 神经激活决定因素的信息， 机电的分子、细胞和功能决定因素 它们的感觉神经末梢的转导在很大程度上是未知的。项目 该 PPG 的 IV 涉及机械感觉的神经生物学。这 项目 (IV.A.1) 于四年前启动，重点关注 1) 结状神经节中 BR 神经元的识别； 2）培养它们 体外； 3）开发机械性能定量系统 激活; 4）通过测量来定义他们的响应 全细胞膜电流，单通道开口 [Ca2+]i。一个 通过测量寻找细胞机制的功能相关性 体内颈动脉窦神经活动。基于非常令人兴奋的 初步研究，我们现在建议检验以下假设： ENaC/degenerin 蛋白家族代表离子通道，负责 BR 神经元中的机电转导。该假设获得了 触摸与触摸之间存在遗传联系的发现提供了强有力的理由 线虫的感觉和机械激活的证据 ENaC/简并蛋白通道。在初步研究中我们发现 1） ENAC/degenerin、γ ENaC 亚基； beta ENaC 和 BNC1（最近 从大脑克隆），在主动脉弓外膜中表达 BR神经末梢和BR神经元所在的结状神经节， 分别; 2) BNC1a（转染卵母细胞）的活性为 被 Gd3+ 阻断，Gd3+ 是一种已知的机械感觉通道阻断剂； 3） 机械刺激期间 BR 神经元中 [Ca2+]i 的升高被 阿米洛利，一种已知的 ENaC/degenerin 通道阻断剂。我们的目标是： 首先，识别 ENaC/degenerin ENaC/degenerin 通道；第三，到 尝试破坏 BR 对机械刺激的反应 通过转染显性的细胞、器官和整个动物水平 ENaC/退化蛋白家族的阴性。 该项目的独特之处在于两个领先的公司的结合 实验室，具有自主控制神经生物学方面的专业知识（Abboud） 以及离子通道的分子生物学（威尔士语）。随着添加的 影像、转基因动物、基因优秀核心支持 转移，成功追求这个问题的承诺是 确定。