Angiotensin-(3-7) pressor effect at the rostral ventrolateral medulla.
Ang-(3-7) is a fragment of the renin-angiotensin system that can be derived both from Ang II or Ang-(1-7). In the present study we determined the cardiovascular effects produced by angiotensin-(3-7) [Ang-(3-7)] microinjection into the rostral ventrolateral medulla (RVLM), a key region for the control of sympathetic drive to the periphery. RVLM microinjection of Ang-(3-7) (20, 40 or 80 ng) in male Wistar rats anesthetized with urethane produced significant increases in MAP (19+/-3.8 mm Hg, n=5; 16+/-1.6 mm Hg, n=15 and 11+/-1.2 mm Hg, n=4, respectively) as compared to saline (4+/-0.7 mm Hg, n=6). These alterations were similar to that induced by Ang-(1-7) (14+/-1.3 mm Hg, 40 ng; n=12) and Ang II (17+/-2.3 mm Hg, 40 ng; n=7). Microinjection of losartan (AT(1) receptor antagonist, 100 pmol) or A779 (selective Mas receptor antagonist, 100 pmol) did not alter the pressor effect caused by Ang-(3-7). Microinjection of an Ang-(3-7) analogue, d-Ala(7)-Ang-(3-7) (100 pmol), completely abolished the pressor effect caused by Ang-(3-7). These results suggest that Ang-(3-7) may be an additional peptide of the RAS to act as neuromodulator, at least at the RVLM. Further, the Ang-(3-7) pressor effect is not mediated by the interaction with AT(1) or the Ang-(1-7), Mas, receptors.
Ferreira
Patrícia Maria
PM
Departamento de Fisiologia e Biofísica, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, 31270-901 MG, Brazil.
Souza Dos Santos
Robson Augusto
RA
Campagnole-Santos
Maria José
MJ
D018686:Anesthetics, Intravenous / Q000494:pharmacology; D000803:Angiotensin I / Q000008:administration & dosage / Q000037:antagonists & inhibitors / Q000494:pharmacology*; D000804:Angiotensin II / Q000031:analogs & derivatives / Q000494:pharmacology; D000818:Animals; D000959:Antihypertensive Agents / Q000494:pharmacology*; D001794:Blood Pressure / Q000187:drug effects*; D004305:Dose-Response Relationship, Drug; D006339:Heart Rate / Q000187:drug effects; D019808:Losartan / Q000494:pharmacology; D008297:Male; D008526:Medulla Oblongata / Q000033:anatomy & histology* / Q000187:drug effects*; D008845:Microinjections; D010446:Peptide Fragments / Q000008:administration & dosage / Q000037:antagonists & inhibitors / Q000494:pharmacology*; D011673:Pulsatile Flow / Q000187:drug effects; D051381:Rats; D017208:Rats, Wistar; D014520:Urethane / Q000494:pharmacology
C092006:7-Ala-angiotensin (1-7); D018686:Anesthetics, Intravenous; D000959:Antihypertensive Agents; D010446:Peptide Fragments; D000804:Angiotensin II; D014520:Urethane; D000803:Angiotensin I; C118790:angiotensin I (1-7); D019808:Losartan