Arterial Blood Pressure in eNOS Knockout Mice

描述(由申请人提供)：本项目的总体目标是了解内皮型一氧化氮合酶(ENOS)释放一氧化氮(NO)、血管紧张素II(Ang11)循环水平与动脉血压调节之间的关系。这一目标将通过将新开发的方法学与各种独特的细胞、分子和生理学技术相结合来实现，以测量清醒小鼠的液体和电解质稳态以及血压。我们将检验这一假设，即内皮细胞内皮型一氧化氮合酶产生的NO是对抗血管紧张素转换酶11的高血压作用的主要缓冲机制。作为这一基本假设的推论，我们进一步推论，选择性抑制或消除内皮细胞中NO的产生将导致不依赖于NaCI摄入量的高血压，而抑制肾小管结构中的NOS将导致钠敏感型高血压。目的1利用独特的细胞和分子技术研究野生型(WT)和内皮型一氧化氮合酶(ENOS)缺失突变(-/-)小鼠肾小管和血管节段一氧化氮合酶亚型的分布和一氧化氮合酶活性的变化，以及在循环Ang11和/或氯化钠摄入量改变过程中这些节段一氧化氮合酶表达的变化。目的2将利用新技术在麻醉小鼠体内进行微透析，并采集清醒小鼠的动脉血，以表征WT和eNOS(-/-)小鼠循环血管紧张素转换酶、膳食钠摄入量和肾脏NO产生之间的相互作用。目的3将使用能够长期监测清醒小鼠的心血管/肾脏变量的方法，确定WT和eNOS(-/-)小鼠循环Ang11和/或饮食钠摄入量的变化对功能的影响。总之，这种新的实验方法组合将被用来确定eNOS来源的NO在调节血管收缩和Ang11在清醒小鼠的升压效应中的重要作用。这些在清醒小鼠身上的研究结果应该会为eNOS衍生的NO在控制肾功能和动脉血压中的作用提供新的理解。此外，这些研究的结果还可能为了解高血压和高血压相关并发症的原因提供重要的见解，高血压和高血压相关并发症是美国死亡和发病率的主要原因。

DESCRIPTION (provided by applicant): The overall goal of this project is to achieve an understanding of the relationship between nitric oxide (NO) release from endothelial NO synthase (eNOS), the circulating levels of angiotensin II (Angll), and the regulation of arterial blood pressure. This goal will be addressed by combining newly developed methodology to measure fluid and electrolyte homeostasis and blood pressure in conscious mice with a variety of unique cellular, molecular, and physiological techniques. We will test the hypothesis that NO produced from eNOS in endothelial cells is the primary buffering mechanism against the prohypertensive actions of Angll. As a corollary to this primary hypothesis, we further theorize that selective inhibition, or elimination, of NO production in endothelial cells will lead to hypertension that is independent of NaCI intake while inhibition of NOS in renal tubular structures will lead to sodium-sensitive hypertension. Aim 1 will utilize unique cellular and molecular techniques to characterize the distribution of NOS isoforms and NOS enzymatic activity in microdissected renal tubular and vascular segments of wild-type (WT) and eNOS null mutant (-/-) mice and to determine the changes in NOS expression in these segments during alterations in circulating Angll and/or sodium chloride intake. Aim 2 will employ novel techniques to perform in vivo microdialysis in anesthetized mice and sample arterial blood from conscious mice to characterize the interaction between circulating Angll, dietary sodium intake, and renal NO production in WT and eNOS(-/-)mice. Aim 3 will determine the functional effects of changes in circulating Angll and/or dietary sodium intake in WT and eNOS(-/-) mice using methodology which permits long-term monitoring of cardiovascular/renal variables in conscious mice. Together, this novel combination of experimental methods will be used to determine the important role of NO derived from eNOS in the modulation of the vasoconstrictor and prohypertensive effects of Angll in the conscious mouse. Results of these studies in conscious mice should provide new understanding of the role of eNOS-derived NO in the control of renal function and arterial blood pressure. Moreover, the results of these studies may also provide important insight into the causes of hypertension and hypertension-related complications that are a leading cause of death and morbidity in the US.