Are multiple angiotensin receptor types involved in angiotensin (1-7) actions on isolated rat portal vein.
Angiotensin (1-7) [Ang (1-7)] is a bioactive component of the renin angiotensin system. Ang (1-7) may interact with angiotensin type 1 (AT1) or type 2 (AT2) receptors and with Ang (1-7) - specific receptors. We examined the interactions between different doses of Ang (1-7) (1 nM-1 microM) and angiotensin II (Ang II) (10 and 100 nM) on isolated rat portal vein. In endothelium-denuded portal vein rings, Ang (1-7) inhibited contractile effects induced by Ang II. The effects of Ang (1-7) were modified by indomethacin, N(G)-nitro-L-arginine methyl ester (L-NAME), (D-Ala7)-Angiotensin (1-7) (H-2888) and losartan. Our results suggest that on rat isolated portal vein rings without endothelium, Ang (1-7) reduces Ang II-induced contractions by acting mostly on Ang (1-7) specific receptors, and this effect is mediated by vasodilatatory prostaglandins. At high concentrations, Ang (1-7) effects are mediated by AT1-receptors, though to a lesser extent than by Ang (1-7) specific receptors.
Department of Physiology, Faculty of Dentistry, University of Medicine and Pharmacy "Gr. T. Popa", Iasi, RO-700115, Romania.
Bogdan
B
Gurzu
Marcel
M
Costuleanu
Simona Mihaela
SM
Slatineanu
Aurica
A
Ciobanu
Gheorghe
G
Petrescu
D000803:Angiotensin I / Q000494:pharmacology*; D000804:Angiotensin II / Q000494:pharmacology; D047228:Angiotensin II Type 1 Receptor Blockers / Q000494:pharmacology; D000818:Animals; D004730:Endothelium, Vascular / Q000502:physiology; D004791:Enzyme Inhibitors / Q000494:pharmacology; D066298:In Vitro Techniques; D008297:Male; D009119:Muscle Contraction / Q000187:drug effects; D009131:Muscle, Smooth, Vascular / Q000187:drug effects*; D019331:NG-Nitroarginine Methyl Ester / Q000494:pharmacology; D019001:Nitric Oxide Synthase / Q000037:antagonists & inhibitors; D010446:Peptide Fragments / Q000494:pharmacology*; D011169:Portal Vein / Q000187:drug effects*; D051381:Rats; D011945:Receptors, Angiotensin / Q000187:drug effects*
D047228:Angiotensin II Type 1 Receptor Blockers; D004791:Enzyme Inhibitors; D010446:Peptide Fragments; D011945:Receptors, Angiotensin; D000804:Angiotensin II; D000803:Angiotensin I; D019001:Nitric Oxide Synthase; C118790:angiotensin I (1-7); D019331:NG-Nitroarginine Methyl Ester