Fast calcium responses along arteriolar endothelium in vivo

体内沿小动脉内皮的快速钙反应

• 批准号: 7750745
• 负责人: Pooneh Bagher
• 金额: $ 5.01万
• 依托单位: UNIVERSITY OF MISSOURI-COLUMBIA
• 依托单位国家: 美国
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-08-01 至 2011-02-28
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7750745
• 关键词: Abbreviations; Acetylcholine; Aging; Agonist; Atropine; Blood; Blood Circulation; Blood Flow Velocity; Blood flow; Bradykinin; Calcium; Calcium Signaling; Cardiovascular Diseases; Cells; Convection; Development; Diabetes Mellitus; Dyes; Endothelial Cells; Endothelium; Endothelium-Dependent Relaxing Factors; Erythrocytes; Event; Goals; Gold; Hypertension; Imagery; Individual; Ischemia; Label; Laboratories; Mediating; Microcirculation; Microspheres; Modeling; Morphologic artifacts; Movement; Muscarinic Acetylcholine Receptor; Nature; Nitric Oxide; Nutrient; Oxygen; Preparation; Proteins; Relaxation; Research; Resistance; Role; Signal Pathway; Signal Transduction; Site; Smooth Muscle Myocytes; Source; Stream; Substance P; Testing; Tissues; Tracer; Transcriptional Regulation; Transgenic Mice; Travel; Vasodilation; Vasodilator Agents; Work; arteriole; constriction; improved; in vivo; insight; millimeter; novel; novel therapeutic intervention; novel therapeutics; receptor; research study; response; shear stress

DESCRIPTION (provided by applicant): The long term research goals of our laboratory center on defining the signaling events that coordinate the activity of individual endothelial cells (EC) and smooth muscle cells (SMC) along microvessels that regulate blood flow to active tissue. Our working hypothesis is that the local control of blood flow represents a coordinated activity among the cells that comprise the walls of arterioles in microvascular resistance networks. Stimulating with acetylcholine (ACh) initiates signals that propagate from cell to cell along the endothelium to initiate SMC relaxation and thereby produce vasodilation. Our laboratory has shown that ACh initiates a bi-directional Ca2+ wave that propagates at -0.1 millimeter per second over distances of several hundred micrometers and stimulates the release of nitric oxide to promote vasodilation. My preliminary experiments have revealed a novel 'Fast Calcium Response (FOR)' that travels much more rapidly (millimeters per second) and for far greater distances but only in the direction of blood flow. The project described herein is focused on understanding how this novel FOR is initiated and propagated along a vessel. Experiments are performed in vivo using anesthetized transgenic mice expressing a Ca2+ indicator protein (GCaMP2) targeted specifically to arteriolar endothelial cells. The mechanism of FOR initiation and propagation are unknown. Aim 1 will determine how the FOR is initiated by testing a variety of endothelium-dependent vasodilators (e.g. ACh, bradykinin, substance P, and ATP). I will determine whether entry of the vasodilator agonist into the blood stream and its convection along the flow path can explain the FOR. Alternatively, a secondary substance may be produced in response to such agonists that in turn triggers the FOR. I will resolve this question using microoclusion to control blood flow distribution in arteriolar networks and by microperfusing defined segments with specific antagonists. Aim 2 will determine how the FOR is actually propagated in relation to the movement of blood. By introducing fluorescent tracers of blood flow (labeled microspheres and red blood cells), I will determine the relationship between FOR and the velocity and distribution of blood flow. Resolving the nature of the FCR will provide new insight for considering how this previously unrecognized signaling pathway is regulated in vivo. In turn, this unique understanding may be applied to developing new therapeutic approaches for treating such pathophysiological conditions such as diabetes, hypertension and ischemia, where, the functional integrity of microvascular EC and SMC are compromised. My overall goal is to apply the findings of my research to understanding and treating cardiovascular disease.

描述（由申请人提供）：我们实验室的长期研究目标集中在定义信号传导事件，这些信号传导事件协调个体内皮细胞（EC）和平滑肌细胞（SMC）沿着微血管的活性，微血管调节流向活性组织的血流。我们的工作假设是，血流的局部控制代表了构成微血管阻力网络中小动脉壁的细胞之间的协调活动。用乙酰胆碱（ACh）刺激引发信号，所述信号沿内皮沿着从细胞传播到细胞以引发SMC松弛，从而产生血管舒张。我们的实验室已经表明，ACh启动双向Ca 2+波，以每秒-0.1毫米的速度在数百微米的距离上传播，并刺激一氧化氮的释放以促进血管舒张。我的初步实验揭示了一种新的“快速钙反应（FOR）”，它的速度要快得多（每秒毫米），距离也要远得多，但只在血液流动的方向上。本文描述的项目集中于理解这种新颖的FOR是如何沿着血管沿着传播的。使用表达特异性靶向小动脉内皮细胞的Ca 2+指示蛋白（GCaMP 2）的麻醉转基因小鼠进行体内实验。FOR引发和传播的机制尚不清楚。目标1将通过测试各种内皮依赖性血管扩张剂（如乙酰胆碱、缓激肽、P物质和ATP）来确定FOR是如何启动的。我将确定血管扩张激动剂进入血流及其沿血流路径的对流沿着是否可以解释FOR。或者，可以响应于这样的激动剂产生第二物质，其继而触发FOR。我将解决这个问题，使用微闭塞控制血流分布在小动脉网络和微灌注特定节段与特定的拮抗剂。目标2将确定FOR实际上是如何相对于血液运动传播的。通过引入血流的荧光示踪剂（标记微球和红细胞），我将确定FOR与血流速度和分布之间的关系。解决FCR的性质将提供新的见解，考虑如何在体内调节这种以前未被认识到的信号通路。反过来，这种独特的理解可以应用于开发新的治疗方法，用于治疗这种病理生理条件，如糖尿病，高血压和缺血，其中，微血管EC和SMC的功能完整性受到损害。我的总体目标是将我的研究成果应用于理解和治疗心血管疾病。