title: Effects of diltiazem on renal blood flow and renal function during angiotensin II infusion in anesthetized dogs.
abstract: Effects of diltiazem on renal blood flow and renal function were studied under angiotensin II-loaded condition in anesthetized dogs. Intravenous infusion of angiotensin II at a rate of 0.25 microgram/kg/min produced an increase in blood pressure by 30 to 40 mmHg and a decrease in renal blood flow by 30 to 40%, resulting in a 100% increase in renal vascular resistance. Under this condition, diltiazem exhibited a dose related increase in renal blood flow not only by intrarenal administration (1-30 micrograms/kg) but also by intravenous administration (10-200 micrograms/kg). The effect was greatly augmented, compared to that observed in a control angiotensin II-unloaded condition. Under angiotensin II-loaded condition, glomerular filtration rate and para-amino-hippuric acid clearance, as well as renal blood flow, were markedly reduced, the levels of which were recovered by intrarenal administration of diltiazem (10 micrograms/kg/min) accompanied by marked natriuresis. The natriuretic effect of diltiazem was also observed by intravenous administration (100 micrograms/kg). It is suggested that the improving effects of diltiazem on renal hemodynamics and renal function, under angiotensin II-loaded condition, are mainly due to its inhibitory action on angiotensin II-evoked renal vasoconstriction, resulting from its calcium antagonistic action.
mesh_terms: D000804:Angiotensin II / Q000037:antagonists & inhibitors / Q000494:pharmacology*; D000818:Animals; D001552:Benzazepines / Q000494:pharmacology*; D001794:Blood Pressure / Q000187:drug effects; D004110:Diltiazem / Q000008:administration & dosage / Q000494:pharmacology*; D004231:Diuresis / Q000187:drug effects; D004285:Dogs; D007261:Infusions, Intra-Arterial; D007275:Injections, Intravenous; D007668:Kidney / Q000187:drug effects*; D008297:Male; D009318:Natriuresis / Q000187:drug effects; D010208:Papaverine / Q000494:pharmacology; D012077:Renal Artery; D012079:Renal Circulation / Q000187:drug effects*; D014655:Vascular Resistance / Q000187:drug effects
chemical_list: D001552:Benzazepines; D000804:Angiotensin II; D010208:Papaverine; D004110:Diltiazem