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.

肾脏内的ANG II作用与5月的人类高血压模型有关。当以最初的亚压剂剂量注入时，ANG II会导致缓慢的压力反应，并且随着时间的推移会增加肾脏传入小动脉的有效收缩。我们将研究以下概念：肾脏传入小动脉对ANG II的反应性取决于源自P47/Phox依赖性NAD NAD（P）H氧化酶的活性氧（ROS）的产生。氧化应激的这些作用是通过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信号级联反应的氧化防御机制来应对的，该信号级联受到组成性多巴胺5受体（D5-R）的调节，我们将测试氧化应激在肾脏中的功能效应，以增强肾脏的效果。相反，肠系膜电阻容器的音调可能会被内皮依赖性超极化因子（EDHF）钝化，其响应实际上可能是由R​​OS介导的。氧化应激的这些差异作用可以提供通过ROS介导的ANG II对肾脏传入小动脉的选择性作用。研究将对比小鼠的分离传入和肠系膜耐药血管。收缩或松弛的测量将与通过荧光显微镜的血管[NO]和[ROS]评估以及对这些血管中关键介质的mRNA和蛋白质表达的测量有关。第一个目标将利用P47/Phox NAD（P）H氧化酶和Enos基因敲除小鼠来定义这些系统在急性微血管对ANG II的响应中的作用。第二个目标将评估长时间ANG II输注过程中微血管中关键氧化酶和抗氧化剂和途径的表达。第三个目标将检查找到罪的功能后果2。它将对比乙酰胆碱诱导的传入和肠系膜动脉中的松弛，并研究O2依赖性变化ROS的产生的影响。在长期输注ANG II或媒介物对与血管[NO]和[ROS]相关的弛豫过程中，将从小鼠中剖析小鼠，并在eNOS，P47/PHOX，EC-SOD和D5-R中删除的模型中剖析。这些方案是研究ROS在ANG II引起的高血压的肾脏机理中的作用的综合方法的一部分。