Arterial Blood Pressure in eNOS Knockout Mice

描述（由申请人提供）：该项目的总体目标是了解内皮NO合成酶（eNOS）释放一氧化氮（NO）、血管紧张素II （Angll）循环水平和动脉血压调节之间的关系。这一目标将通过结合新开发的方法来测量液体和电解质稳态以及有意识小鼠的血压，以及各种独特的细胞，分子和生理技术来解决。我们将验证内皮细胞中eNOS产生的NO是Angll预防高血压作用的主要缓冲机制的假设。作为这一主要假设的推论，我们进一步推论内皮细胞中选择性抑制或消除NO的产生将导致不依赖于NaCI摄入的高血压，而抑制肾小管结构中的NOS将导致钠敏感性高血压。目的1将利用独特的细胞和分子技术来表征野生型（WT）和eNOS零突变（-/-）小鼠微解剖肾小管和血管段中NOS异构体的分布和NOS酶活性，并确定在循环Angll和/或氯化钠摄入量改变时这些段中NOS表达的变化。目的2将采用新技术对麻醉小鼠进行体内微透析，并对清醒小鼠的动脉血进行取样，以表征WT和eNOS（-/-）小鼠的循环Angll、饮食钠摄入量和肾NO生成之间的相互作用。目的3将使用允许长期监测有意识小鼠心血管/肾脏变量的方法，确定WT和eNOS（-/-）小鼠循环Angll和/或饮食钠摄入量变化的功能影响。总之，这种新颖的实验方法组合将用于确定eNOS衍生的NO在清醒小鼠Angll血管收缩和高血压作用的调节中的重要作用。这些在清醒小鼠中的研究结果应该为enos来源的NO在控制肾功能和动脉血压中的作用提供新的认识。此外，这些研究的结果也可能为高血压和高血压相关并发症的病因提供重要的见解，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.