In vivo visualization of angiotensin II- and tubuloglomerular feedback-mediated renal vasoconstriction.

摘要: In vivo visualization of angiotensin II- and tubuloglomerular feedback-mediated renal vasoconstriction. Background A noninvasive technique to monitor microcirculation would be a useful tool for investigation disease the effects drugs on system. We have developed novel, less invasive visualize in using an intravital tapered-tip (1mm o) lens-probe (pencil lens-probe) videomicroscopy, which only requires insertion probe into superficial cortex situ. Methods To assess validity this technique, II (Ang II) intrarenal sodium chloride loading (activator mechanism) were examined. The microvasculature was successfully visualized monitored. Results Administration Ang (1, 3, 10 30 ng/kg/min) produced dose-dependent constriction afferent efferent arterioles similar degrees; at ng/kg/min, elicited 52 ± 3 ( N = 9) 53 3% decreases diameter 9), respectively. II-induced arteriolar completely prevented by losartan, type 1 (AT1) antagonist. hypertonic saline administration transient increments (from 98 8 122 7 mL/min, 6, P 3) arterioles. Furthermore, response inhibited furosemide, feedback inhibitor. Conclusion pencil videomicroscopy can powerful observation microcirculation, with intact microvascular responses two important homeostatic mechanisms, feedback.