Hansell P
Department of Physiology & Medical Biophysics, University of Uppsala, Sweden.
Ups J Med Sci. 1993;98(2):149-58. doi: 10.3109/03009739309179308.
Previous studies from our laboratory have indicated an important role for angiotensin II (AII) in the regulation of renal medullary haemodynamics during normal physiological conditions. In order to investigate further the influence of endogenous AII on the juxtamedullary vascular resistance in anaesthetized rats the velocity of fluorescently-labeled red cells (vRBC) was measured with a cross-correlation technique in the vasa recta before and after infusion of the angiotensin I- converting enzyme inhibitor captopril or vehicle. Irrespective of treatment, vRBC was higher in the descending vasa recta (DVR) than in the ascending vasa recta (AVR). In time control animals VRBC in DVR and AVR and mean arterial blood pressure (MAP) remained stable over the 45 min study period. In animals receiving captopril (3 mg.h-1.kg-1 bw) vRBC increased almost proportionally in DVR and AVR; by 26% in DVR (from 1.02 +/- 0.12 to 1.28 +/- 0.10 mm.s-1, p < 0.05) and by 19% in AVR (from 0.46 +/- 0.05 to 0.55 +/- 0.07 mm.s-1, p < 0.05). MAP decreased by 9% (from 107 +/- 3 to 97 +/- 2 mm Hg, p < 0.05). These results give further support to the suggestion of an involvement of AII in the regulation of juxtamedullary vascular resistance during normal physiological conditions.
我们实验室之前的研究表明，在正常生理条件下，血管紧张素II（AII）在肾髓质血流动力学调节中起重要作用。为了进一步研究内源性AII对麻醉大鼠近髓血管阻力的影响，在输注血管紧张素I转换酶抑制剂卡托普利或赋形剂前后，采用互相关技术测量直小血管中荧光标记红细胞的速度（vRBC）。无论治疗如何，直小血管降支（DVR）中的vRBC均高于直小血管升支（AVR）。在时间对照动物中，DVR和AVR中的VRBC以及平均动脉血压（MAP）在45分钟的研究期间保持稳定。在接受卡托普利（3mg·h-1·kg-1体重）的动物中，DVR和AVR中的vRBC几乎成比例增加；DVR中增加26%（从1.02±0.12增至1.28±0.10mm·s-1，p<0.05），AVR中增加19%（从0.46±0.05增至0.55±0.07mm·s-1，p<0.05）。MAP下降9%（从107±3降至97±2mmHg，p<0.05）。这些结果进一步支持了AII参与正常生理条件下近髓血管阻力调节的观点。
