MECHANISM OF CORONARY ENDOTHELIUM MEDIATED VASODILATION

内皮依赖性血管扩张在动脉粥样硬化中起重要作用 冠状动脉血管张力的控制。一种内皮细胞衍生的 超极化因子、环氧二十烷酸(EETs)和内皮- 衍生的松弛因子，一氧化氮(NO)已被报道为 激活血管平滑肌K+通道，扩张冠脉 船只。然而，EET和NO激活K+的机制 频道仍然未知。最近，几个重要的观察结果 提示细胞内ADP-核糖可能作为新的第二种 调节非血管组织中细胞功能的信使。我们的 初步研究结果还表明，环状ADP-核糖和ADP- 核糖可能参与冠状动脉K+通道的门控 平滑肌和EETs改变这些信号的新陈代谢 核苷酸。拟议研究的目的是确定 环状ADP-核糖和ADP-核糖在钾门控中的作用 小鼠血管平滑肌细胞的(K+)通道 冠状动脉和这些核苷酸对心脏的作用 内源性血管扩张剂EETs和NO_2对K+通道的影响 活跃度和血管张力。我们将首先对酶进行表征 CADP-R和ADP-R在冠脉血管中的代谢途径 并明确了其动力学特性和调控机制。 这些途径中的关键酶。这些新的核苷酸将是 离子对反相高效液相色谱检测技术及其应用 结构将使用质谱学进行鉴定。A淋巴细胞 分化抗原CD38，具有多种活性，包括 环状ADP-核糖的产生和水解将在 冠状动脉血管平滑肌。我们将确定角色 环状ADP-核糖和ADP-核糖在钾通道门控中的作用 定义由环状ADP-核糖门控的K+通道类型 应用膜片钳技术制备ADP-核糖。我们还将探索 环状ADP-核糖和ADP-核糖门控K+的分子机制 频道。最后，我们将确定环状ADP-核糖或ADP- 核糖有助于内皮衍生血管扩张剂的作用。 环状ADP-核糖和ADP-核糖在钾通道激活中的作用 用EETs诱导，并检测NO。这些研究将证明 一种新的内皮细胞源性作用的信号通路 血管扩张剂，有助于我们理解细胞和 K+通道门控与冠脉血管调节的分子机制 语气。

Endothelium-dependent vasodilation plays an important role in the control of coronary vascular tone. An endothelium-derived hyperpolarization factor, epoxyeicosanoids (EETs) and an endothelium- derived relaxation factor, nitric oxide (NO) have been reported to activate K+ channel in vascular smooth muscle and dilate coronary vessels. However, the mechanism by which EETs and NO activate K+ channels remains unknown. Recently, several important observations suggest that intracellular ADP-riboses may serve as a new second messenger to regulate cell functions in non-vascular tissues. Our preliminary findings also indicate that cyclic ADP-ribose and ADP- ribose may participate in the gating of K+ channel in coronary vascular smooth muscle and EETs alter the metabolism of these signaling nucleotides. The purpose of the proposed studies is to determine the role of cyclic ADP-ribose and ADP-ribose in the gating of potassium (K+) channels in vascular smooth muscle cells isolated from small coronary arteries and the contribution of these nucleotides to the effect of endogenous vasodilators such as EETs and NO, on K+ channel activity and vascular tone. We will first characterize the enzymatic pathways of cADP-R and ADP-R metabolism in coronary vascular smooth muscle and define the kinetic properties and regulatory mechanism of the key enzymes in these pathways. These novel nucleotides will be measured using ion-pair reverse phase HPLC technique and their structure will be identified using mass spectrometry. A lymphocyte differentiate antigen, CD38 which has multiple activities including the production and hydrolysis of cyclic ADP-ribose will be detected in vascular smooth muscle of coronary arteries. We will determine the role of cyclic ADP-ribose and ADP-ribose in the gating of K+ channels and define the type of K+ channels that is gated by cyclic ADP-ribose and ADP-ribose using patch clamp technique. We will also explore the molecular mechanism by which cyclic ADP-ribose and ADP-ribose gate K+ channels. Finally we will determine whether cyclic ADP-ribose or ADP- ribose contributes to the effect of endothelium-derived vasodilators. The role of cyclic ADP-ribose and ADP-ribose in K+ channel activation induced by EETs and NO will be examined. These studies will demonstrate a new signaling pathway for the action of endothelium-derived vasodilators and contribute to our understanding of cellular and molecular mechanism gating K+ channels and regulating coronary vascular tone.