Haulica Ion, Bild Walther, Mihaila Christian N, Ionita Teodor, Boisteanu Corneliu P, Neagu Bogdan
Labroatory of Experimental and Applied Physiology, The Romanian Academy Iasi, Iasi, Romania.
J Renin Angiotensin Aldosterone Syst. 2003 Jun;4(2):124-8. doi: 10.3317/jraas.2003.013.
Using isolated rat aortic rings perfused with Krebs-Henseleit saline, the vascular effects of angiotensin (1-7) (Ang [1-7]) and its interactions with angiotensin II (Ang II) were investigated. Ang (1-7) induced endothelium-dependent relaxation and vasodilating effects in preparations precontracted with phenylephrine. Without preconstriction, Ang (1-7) at high doses (10(-6) 10(-5) M) produced either a significant inhibition of Ang II-induced vasoconstriction or a non-tachyphylactic vasopressor response. While losartan inhibited the vasoconstriction induced by Ang (1-7), A779 blocked only its relaxation. Unlike losartan, blockade of AT(2)-receptors with PD 123319 had no effect. Taking into account the biphasic effects of angiotensin (1-7), we propose that it is one of the active components of the renin-angiotensin system, which is involved as a modulator both in the counter-regulatory actions of Ang II and in the self-regulation of its own vasodilating effects.
