title: Angiotensin-(1-7) antagonist A-779 attenuates the potentiation of bradykinin by captopril in rats.
abstract: We evaluated the possibility that endogenous angiotensin-(1-7) [Ang-(1-7)] could participate in the potentiation of bradykinin (BK) by the angiotensin-converting enzyme inhibitor (ACEI) captopril in conscious Wistar rats. Catheters were introduced into descending aorta (through the left carotid artery) for BK injection, femoral artery for arterial pressure measurement, and both femoral veins for BK injection and vehicle or Ang-(1-7) antagonist, A-779 infusion. Infusion of vehicle or A-779 started 40 to 45 minutes after captopril administration. Sequential BK dose-response curves were made before, 10 minutes after captopril, and within 10 minutes of infusion of vehicle or A-779. To evaluate angiotensin I conversion, dose-response curves for angiotensin I and angiotensin II were made following the same protocol used for BK. Captopril treatment markedly increased the BK hypotensive effect and significantly decreased angiotensin I conversion. Infusion of A-779 did not modify the angiotensin II pressor effect or the effect of captopril on angiotensin I conversion. However, A-779 significantly reduced the potentiating effect of captopril on the hypotensive effect of BK administered intravenously or intra-arterially. These results suggest that endogenous Ang-(1-7) and/ or an Ang-(1-7)-related peptide plays an important role in the BK potentiation by ACEI through a mechanism not dependent upon inhibition of ACE hydrolytic activity.
authors.affiliation: Department of Physiology and Biophysics, Institute of Biological Sciences, Federal University of Minas Gerais, Belo Horizonte, Brazil.
authors.forename: Luciana Gonçalves
authors.initials: LG
authors.lastname: Maia
authors.forename: Marcela Caldeira
authors.initials: MC
authors.lastname: Ramos
authors.forename: Liliam
authors.initials: L
authors.lastname: Fernandes
authors.forename: Maria Helena Catelli
authors.initials: MH
authors.lastname: de Carvalho
authors.forename: Maria José
authors.initials: MJ
authors.lastname: Campagnole-Santos
authors.forename: Robson Augusto
authors.initials: RA
authors.lastname: Souza dos Santos
mesh_terms: D000803:Angiotensin I / Q000037:antagonists & inhibitors*; D000804:Angiotensin II / Q000031:analogs & derivatives* / Q000494:pharmacology*; D000806:Angiotensin-Converting Enzyme Inhibitors / Q000494:pharmacology*; D000818:Animals; D000959:Antihypertensive Agents / Q000494:pharmacology*; D001920:Bradykinin / Q000378:metabolism*; D002216:Captopril / Q000494:pharmacology*; D004357:Drug Synergism; D006973:Hypertension / Q000188:drug therapy; D007261:Infusions, Intra-Arterial; D007262:Infusions, Intravenous; D008297:Male; D010446:Peptide Fragments / Q000037:antagonists & inhibitors* / Q000494:pharmacology*; D051381:Rats; D017208:Rats, Wistar
chemical_list: C092006:7-Ala-angiotensin (1-7); D000806:Angiotensin-Converting Enzyme Inhibitors; D000959:Antihypertensive Agents; D010446:Peptide Fragments; D000804:Angiotensin II; D000803:Angiotensin I; D002216:Captopril; C118790:angiotensin I (1-7); D001920:Bradykinin