MECHANOTRANSDUCTION BY VASCULAR SMOOTH MUSCLE

该项目的长期目标是了解结构和 血管平滑肌(VSM)机械转导的功能基础。这个 VSM转换物理力(如压力或拉伸)的能力 动脉收缩(肌源性行为)对维持是至关重要的 外周阻力和脑血流自动调节。这 应用程序已进行修改，以采取更系统和更有针对性的 从三个方面探讨肌源性行为的认识 主要现象：生肌张力、生肌反应性的发展 和强制扩张。我们的中心假设是大脑动脉 肌源性张力和反应性是通过一系列互补的， 压力引起的膜功能变化(膜电位、钙 进入)、肌丝调节机制(钙敏感性)和 细胞骨架结构(肌动蛋白聚合)。目标1了解 MT发生的生物物理和机制决定因素。离散型 一旦足够的压力或拉伸，就会发生可测量的事件 施加在血管上，并导致激活细胞 机制，如膜去极化和钙进入， 产生持续的动脉收缩或紧张。我们将测试 假设肌源性音调的出现可能与 血管壁变形的特定水平，并与 阈值膜电位和/或细胞内钙浓度。这个 这些因素的作用以及PKC对它们的调节 确定音调范围的激活/抑制也将是 研究，以及语调发展是 与显著的肌动蛋白聚合有关。目标2是调查 调节肌源性反应性的因素(dphi/dp) 和渗透性容器，并定义自动调节效率 MR作为不同信号转导激活/抑制的函数 怀疑在肌源性反应性中起主要作用的成分。通过使用 评估功能(反应性、膜)的补充方法 电势、胞内钙浓度)和结构变化 激光共聚焦测量G-肌动蛋白荧光和F-肌动蛋白 显微镜和电子显微镜；操纵 药物聚合/解聚剂的细胞骨架)，我们 希望了解跨壁压力与心脏功能的关系 动脉收缩(肌源性反应性)。最后，突然和 这种适应性血管机制在应对急性呼吸道感染时的戏剧性失败 高血压(强迫扩张，高血压的主要事件 脑病-将进行调查，以确定离子的作用 (Vm、钙)、酶(PKC)和细胞骨架(Actin)因子 《创世纪与结局》。

The long-term goal of this project is to understand the structural and functional basis for vascular smooth muscle (VSM) mechanotransduction. The ability of VSM to transduce physical forces such as pressure or stretch into arterial constriction (myogenic behavior) is vital for maintaining peripheral resistance and cerebral blood flow autoregulation. This application has been revised to take a more systematic and focused approach towards understanding myogenic behavior by examining three principal phenomena: the development of myogenic tone, myogenic reactivity and forced dilation. Our central hypothesis is that cerebral artery myogenic tone and reactivity are effected via a series of complementary, pressure-induced changes in membrane function (membrane potential, calcium entry), myofilament regulatory mechanisms (calcium sensitivity) and cytoskeletal structure (actin polymerization). Aim 1 to understand the biophysical and mechanistic determinants of MT development. The discrete and measurable event occurs once a sufficient pressure or stretch has been imposed upon the vessel, and results in the activation of cellular mechanisms, such as membrane depolarization and calcium entry, that produce sustained arterial constriction or tone. We will test the hypothesis that the appearance of myogenic tone can be related to a specific level of vascular wall deformation, and is associated with a threshold membrane potential and/or cytosolic calcium concentration. The role of these factors, and of their modulation by PKC activation/inhibition in determining the extent of tone will also be investigated, as will the hypothesis that development of tone is associated with significant actin polymerization. Aim 2 is to investigate the factors that modulate myogenic reactivity (dphi/dP) by using intact and permeabilized vessels, and to define the autoregulatory efficiency of MR as a function of activation/inhibition of different signal transduction components suspected to play a major role in myogenic reactivity. By using complementary approaches to evaluate functional (reactivity, membrane potential, cytosolic calcium concentration) and structural changes (measuring G actin fluorescence and F actin by using laser confocal microscopy and electron microscopy; manipulating the state of the cytoskeleton by pharmacological polymerizing/depolymerizing agents), we hope to understand the relationship between transmural pressure and arterial constriction (myogenic reactivity). Finally, the sudden and dramatic failure of this adaptive vascular mechanism in response to acute hypertension (forced dilation, a cardinal event in hypertensive encephalopathy- AIM 3) will be investigated to determine the role of ionic (VM, calcium), enzymatic (PKC) and cytoskeletal (actin) factors in its genesis and outcome.