title: Angiotensin-converting enzyme inhibition with quinapril (CI-906) and captopril in spontaneously hypertensive rats with suppressed renin-angiotensin system.
abstract: Renin- and nonrenin-mediated antihypertensive actions of angiotensin-converting enzyme (ACE) inhibitors were investigated in young spontaneously hypertensive rats (SHR). Renin was suppressed either by removal of 2/3 of the renal mass, deoxycorticosterone (DOC) treatment, or 1% of NaCl in drinking water. Blood pressure responses to the nonsulfhydryl ACE inhibitor quinapril (CI-906) and the sulfhydryl inhibitor captopril, given orally for 2 days each, were examined by the tail cuff method. The marked depressor responses observed in control SHR were attenuated by the different manipulations in a manner clearly related to suppression of plasma renin activity (PRA). The decrease in blood pressure falls and in PRA was smallest in partially nephrectomized SHR. The mineralocorticoid (DOC) administration or 1% NaCl reduced PRA and the responses to ACE inhibitors markedly, though not completely. In a further experiment, severe salt retention induced by DOC and NaCl in uninephrectomized SHR suppressed PRA to an unmeasurable level and prevented the depressor action of a large dose of captopril. The results suggest that in SHR the acute blood pressure-lowering effect of ACE inhibitors is completely dependent on the renin-angiotensin system. The experiments also show that this system clearly participates in the support of rapidly increasing blood pressure in young SHR.
authors.affiliation: Department of Biomedical Sciences, University of Tampere, Finland.
authors.forename: P
authors.initials: P
authors.lastname: Säynävälammi
authors.forename: I
authors.initials: I
authors.lastname: Pörsti
mesh_terms: D000806:Angiotensin-Converting Enzyme Inhibitors / Q000494:pharmacology*; D000818:Animals; D001794:Blood Pressure / Q000187:drug effects; D002216:Captopril / Q000494:pharmacology*; D003900:Desoxycorticosterone / Q000494:pharmacology; D007546:Isoquinolines / Q000494:pharmacology*; D008297:Male; D009392:Nephrectomy; D000077583:Quinapril; D051381:Rats; D011918:Rats, Inbred SHR; D012083:Renin / Q000097:blood; D012084:Renin-Angiotensin System / Q000187:drug effects*; D044005:Tetrahydroisoquinolines
chemical_list: D000806:Angiotensin-Converting Enzyme Inhibitors; D007546:Isoquinolines; D044005:Tetrahydroisoquinolines; D003900:Desoxycorticosterone; D002216:Captopril; D012083:Renin; D000077583:Quinapril