The renal antihypertensive effect of angiotensin I converting enzyme inhibitors.
Intrarenal administration of angiotensin I converting enzyme (ACE) inhibitors carried out in norepinephrine- (NE; 2-4 micrograms/kg per min) or in angiotensin II- (ANG II; 60-90 ng/kg per min) induced acute hypertension in conscious unrestrained rabbits. Intrarenal administration of captopril (5 mg/kg) and MK-422 (1 mg/kg) caused no significant effect when injected intravenously. However, it showed a prompt and marked depressor effect in NE- but not in ANG II-induced hypertension. This effect was not observed after intrarenal infusion of saralasin (2 and 10 micrograms/kg per min) in NE-induced hypertension. While pretreatment with aprotinin or indomethacin failed to inhibit the depressor action, 2-bromoethylamine hydrobromide (BEA), which is known to induce necrosis of the renal papilla, produced complete abolition of the depressor effect of an intrarenal injection of MK-422 in NE-induced hypertension. These results indicate that the kidney plays an important role in the depressor action of ACE inhibitors in NE- but not in ANG II-induced acute hypertension, and that this effect may be related to the potentiation of antihypertensive renomedullary lipids rather than the inhibition of the renin-angiotensin system or the potentiation of bradykinin or prostaglandins.
D000208:Acute Disease; D000804:Angiotensin II; D000806:Angiotensin-Converting Enzyme Inhibitors / Q000008:administration & dosage / Q000494:pharmacology*; D000818:Animals; D007611:Aprotinin / Q000494:pharmacology; D005260:Female; D006339:Heart Rate / Q000187:drug effects; D006973:Hypertension / Q000139:chemically induced / Q000503:physiopathology*; D007213:Indomethacin / Q000494:pharmacology; D007668:Kidney / Q000187:drug effects* / Q000502:physiology; D009638:Norepinephrine; D011817:Rabbits; D012504:Saralasin / Q000494:pharmacology
D000806:Angiotensin-Converting Enzyme Inhibitors; D000804:Angiotensin II; D007611:Aprotinin; D012504:Saralasin; D009638:Norepinephrine; D007213:Indomethacin