Regulation of renal afferent arteriolar function by ROS

ROS对肾传入小动脉功能的调节

• 批准号: 6656538
• 负责人: CHRISTOPHER S WILCOX
• 金额: $ 33.6万
• 依托单位: GEORGETOWN UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2002
• 资助国家: 美国
• 起止时间: 2002-09-01 至 2003-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6656538
• 关键词: NAD(P)H oxidoreductase; acetylcholine; angiotensin /renin /aldosterone hypertension; angiotensin II; arterioles; dopamine receptor; fluorescence microscopy; free radical oxygen; gene expression; gene targeting; genetically modified animals; kidney circulation; kidney function; laboratory mouse; nitric oxide synthase; oxidative stress; superoxide dismutase; vascular resistance; vasomotion

Ang II action within the kidneys is implicated in may models of human hypertension. When infused at initially subpressor doses, Ang II causes a slow pressor response with potent constriction of the renal afferent arteriole that increases over time. We will examine the concept that the reactivity of the renal afferent arteriole to Ang II is dependent on the generation of reactive oxygen species (ROS) derived from p47/phox- dependent NAD(P)H oxidase. These effects of oxidative stress are countered by oxidant defense mechanisms mediated via extracellular superoxide dismutase (EC-SOD) and intracellularly via a signaling cascade that is regulated by the constitutively-active dopamine 5 receptor (D5-R), We will test whether the functional effect of oxidative stress in the renal afferent arteriole is to enhance tone by reducing eNOS-derived NO. In contrast, the tone of the mesenteric resistance vessels may be blunted by an endothelium-dependent hyperpolarizing factor (EDHF) whose response may actually be mediated by an ROS. These differential effects of oxidative stress could provide for selective effects of Ang II mediated via ROS, on renal afferent arterioles. Studies will contrast isolated afferent and mesenteric resistance vessels from mice. Measurement of contraction or relaxation will be related to measurements of vascular [NO] and [ROS] assess by fluorescence microscopy and to measurements of the mRNA and protein expression of key mediators in these vessels. The first aim will utilize p47/phox NAD(P)H oxidase and eNOS Knockout mice to define the roles of these systems in the acute microvascular responses to Ang II. The second aim will assess the expression of key oxidases and antioxidant and pathways in microvessels during prolonged Ang II infusion. The third aim will examine the functional consequences of finding sin Aim 2. It will contrast acetylcholine-induced relaxation in afferent and mesenteric arterioles, and study the effect of O2-dependent changes in ROS generation. Arterioles will be dissected from mice during prolonged infusion of Ang II or vehicle to related relaxation to vascular [NO] and [ROS] in models deleted in eNOS, p47/phox, EC-SOD and D5-R. These protocols are part of an integrated approach to studying the roles of ROS in the renal mechanism of Ang II-induced hypertension.

Ang II 在肾脏内的作用与许多人类高血压模型有关。当以最初的亚加压剂量输注时，Ang II 会引起缓慢的升压反应，并随着时间的推移，对肾传入小动脉进行有效的收缩。我们将研究这样的概念：肾传入小动脉对 Ang II 的反应性取决于 p47/phox 依赖性 NAD(P)H 氧化酶衍生的活性氧 (ROS) 的产生。氧化应激的这些影响通过细胞外超氧化物歧化酶 (EC-SOD) 介导的氧化防御机制和细胞内通过组成型活性多巴胺 5 受体 (D5-R) 调节的信号级联反应来抵消。肾传入小动脉氧化应激的作用是通过减少 eNOS 衍生的 NO 来增强张力。相反，肠系膜阻力血管的张力可能会被内皮依赖性超极化因子（EDHF）减弱，其反应实际上可能是由 ROS 介导的。氧化应激的这些不同作用可以通过 ROS 介导的 Ang II 对肾传入小动脉产生选择性作用。研究将对比小鼠的孤立传入血管和肠系膜阻力血管。收缩或舒张的测量将与通过荧光显微镜评估的血管 [NO] 和 [ROS] 的测量以及这些血管中关键介质的 mRNA 和蛋白质表达的测量相关。第一个目标将利用 p47/phox NAD(P)H 氧化酶和 eNOS 基因敲除小鼠来确定这些系统在 Ang II 的急性微血管反应中的作用。第二个目标是评估长期 Ang II 输注过程中关键氧化酶和抗氧化剂的表达以及微血管中的通路。第三个目标将检查发现 sin Aim 2 的功能后果。它将对比乙酰胆碱诱导的传入和肠系膜小动脉松弛，并研究 O2 依赖性变化对 ROS 生成的影响。在删除了 eNOS、p47/phox、EC-SOD 和 D5-R 的模型中，在长时间输注 Ang II 或媒介物期间，将从小鼠身上切下小动脉，以与血管 [NO] 和 [ROS] 相关松弛。这些方案是研究 ROS 在 Ang II 诱导的高血压肾脏机制中的作用的综合方法的一部分。