Murakami S, Bernardo J F, Jacob T D, Branch R A, Sabra R
Center for Clinical Pharmacology, University of Pittsburgh Medical Center, Pa., USA.
Ren Physiol Biochem. 1995 Jul-Aug;18(4):198-208. doi: 10.1159/000173917.
The role of nitric oxide (NO) synthesis in the peripheral vasodilation and sodium retention that occurs after partial portal vein ligation (PVL) was investigated. Hemodynamic studies in PVL rats with sodium retention and in sham-operated controls were conducted on the day when PVL rats developed transient and maximal sodium retention. Measurements were obtained before and during two consecutive periods after NO synthesis inhibition with NG-monomethyl-L-arginine (L-NMMA). Under baseline conditions, PVL rats with sodium retention were hypotensive, with equivalent decreases in total peripheral resistance and glomerular filtration rate in comparison to the control group. After L-NMMA, peripheral resistance and arterial pressure increased by similar extent in both groups. As compared with controls, PVL rats with sodium retention remained hypotensive and vasodilated. Furthermore, L-NMMA-induced natriuresis was attenuated in the PVL group. Additionally, serum and urinary levels of nitrate and nitrite did not vary before surgery and at the time of sodium retention. These results suggest that in PVL rats (1) vasodilation is not NO mediated; (2) vasodilation is not a sufficient explanation for sodium retention, and (3) a sodium-retaining factor acting on the renal tubules is responsible for sodium retention.
研究了一氧化氮（NO）合成在部分门静脉结扎（PVL）后发生的外周血管舒张和钠潴留中的作用。在PVL大鼠出现短暂且最大程度的钠潴留当天，对有钠潴留的PVL大鼠和假手术对照组进行了血流动力学研究。在用NG-单甲基-L-精氨酸（L-NMMA）抑制NO合成之前和之后的两个连续时间段内进行测量。在基线条件下，有钠潴留的PVL大鼠血压降低，与对照组相比，总外周阻力和肾小球滤过率同等程度降低。给予L-NMMA后，两组的外周阻力和动脉压均有相似程度的升高。与对照组相比，有钠潴留的PVL大鼠仍处于低血压状态且血管舒张。此外，L-NMMA诱导的利钠作用在PVL组中减弱。另外，术前和钠潴留时血清及尿液中的硝酸盐和亚硝酸盐水平没有变化。这些结果表明，在PVL大鼠中：（1）血管舒张不是由NO介导的；（2）血管舒张不足以解释钠潴留；（3）作用于肾小管的一种钠潴留因子是钠潴留的原因。
