In vivo observation of intrarenal microvessels and evaluation of the effect of exgenous high dose Angiotensin II forrenal microcirculation by a needle probe video microscope with a CCD camera.

点击翻译按钮获取中文摘要

We visualized intrarenal microvessels by a needle-type video-microscope with a CCD camera (magnification =400). In 5 anesthetized dogs, the needle probe (O.D.=3.5 mm, length =6.5 mm) was introduced into the renal cortex or medulla through the renal capsule from the lateral renal border. Microscopic observation was discontinued when intrarenal bleeding occured (this was recognized by degradation of the image). Systemic Pressure and Renal blood flow after intraarterial infusion of angiotensin II changed significantly. MAP was elevated by angotensin II infusion from (incresed rate 18 (]SY.+-。[) 4 %) after 20 second later and remained high pressure for 3 minutes. Wheres RBF was decreased 25 (]SY.+-。[) 5 % significantly at 20 second which were significant difference, by intra-arterial infusion of 20ug angiotensin II,and returned to the basal level by 120 second. At the same time courese, in the visualized single nephron in vivo, Afferent and efferent arteriole began to be constricted distin … More ctly. At the first time afferent arteriole paticuraly seemmed to be trembled after boulas injection of angiotensin II,on the other hand it appeared vasomotion vigorously too, and the glomerus was shaked accordinaly. After trembling, afferent arteriole began to be constricted apparently at 10 second. The 60 second later, the diameter of afferent arteriole decresed 34% from 14.8 (]SY.+-。[) 4.5 mm, and returend to the basal diameter by 150 seconds. Wheres efferent arteriole was also constricted after 20ug AII infusion, but compeard with afferent arteriole, trembling or vasomotion was very restraind from angiotensin II effect. With the same time course, efferent artry was accordinaly constricted 36% from 13.9 (]SY.+-。[) 40mm, which had significant difference, and recovered by 150 seconds. Compered with affrent A constriction and efferent A constriction, These Arteries were constricted to minimam diameter at the almost same time. At the constricted diameter percentage, which was minimam diameter/maximum diameter at a mesured vessels, afferent Arteriole has a tendency, which was more constricted strongly than efferent arteriole. But two groups had no significant difference of T-test. Exgenous high dose Angiotensin II constricts both afferent arteriole and effernt arteriole in vivo. Less