RENAL MEDULLARY NITRIC OXIDE AND BLOOD PRESSURE

我们实验室以前的数据表明， 肾髓质 一氧化氮合酶在肾功能损害的短期和长期控制中的作用 功能和动脉压。 个人NOS的作用 同种型在控制肾功能和动脉压中的作用 不清楚 我们实验室最近的工作表明， 诱导型一氧化氮合酶（INOS）在肾脏中以高水平存在， 正常大鼠延髓和慢性全身性iNOS抑制导致 动脉压升高 该提案将解决 假设肾髓质iNOS的表达差异， 正常大鼠肾髓质中的不同细胞类型， 通过直接作用影响钠和水的排泄， 结肠导管的一部分 本提案的前半部分将进行实验， 确定急性和慢性液体和电解质平衡， 肾髓质选择性抑制对血压的影响 iNOS。 这些实验将使用技术进行 我们实验室独有的（用于激光的植入光纤- 多普勒血流仪和选择性直接注入肾脏 髓质间质空间），因为肾髓质iNOS被抑制 选择性酶抑制剂。 抑制的确认将 通过体外测量NOS酶活性来确定， 从处理的动物获得的组织。 这些实验将 证明了iNOS在钠调节中的重要性， 水平衡和血压。 提案后半部分的实验将侧重于 诱导型一氧化氮合酶在肾小管上皮细胞中分布及其功能意义 和血管节段的变化。比较 mRNA水平、免疫反应蛋白水平和钙离子水平。 依赖性和非依赖性NOS酶活性最初 对从维持在 低、正常或高钠摄入量。 定量RT-PCR 然后将使用iNOS mRNA的测量来确定 iNOS消息在 显微解剖的肾髓质管状和/或血管节段。 最后，钠摄入量与血压的关系 在长期给予选择性iNOS抑制剂的大鼠中， 将被确定为，以便绘制与 肾髓质结构中iNOS的变化。

Previous data from our laboratory demonstrated the importance of renal medullary. NOS in the short- and long-term control of renal function and arterial pressure. The role of the individual NOS isoforms in the control of renal function and arterial pressure is not clear. Recent work from our laboratory indicates that inducible NOS (INOS) is present in high levels in the renal medulla of normal rats and chronic systemic iNOS inhibition leads to an elevation of arterial pressure. This proposal will address the hypothesis that renal medullary iNOS is differentially expressed in different cell types in the renal medulla of normal rates and influences sodium and water excretion by direct effects at the level of the colocynth duct. Experiments will be performed in the first half of this proposal to determine the acute and chronic fluid and electrolyte balance and blood pressure effects of selective inhibition of renal medullary iNOS. These experiments will be performed using techniques unique to our laboratory (implanted optical fibers for laser- Doppler flometery and selective infusion directly into the renal medullary interstitial space) as renal medullar iNOS is inhibited with selective enzyme inhibitors. Confirmation of inhibition will be determined by in vitro measures of NOS enzyme activity in tissues obtained from the treated animals. These experiments will demonstrate the importance of iNOS in the regulation of sodium and water balance and blood pressure. The experiments in the second half of the proposal will focus on the distribution and functional importance of iNOS in renal tubular and vascular segments as sodium intake is changed. comparison of mRNA levels, immunoreactive protein levels, and calcium- dependent and -independent NOS enzymatic activity will initially be performed on whole tissue obtained from rats maintained on a low, normal, or high sodium intake. Quantitative RT-PCR measurements of mRNA for iNOS will then be used to determine the location and relative quantity of iNOS message in microdissected renal medullary tubular and/or vascular segments. Finally, the relationship between sodium intake and blood pressure in rats chronically administered with the selective iNOS inhibitors will be determined to in order to draw a functional correlate with the observed changes in iNOS in renal medullary structures.