Interactions between angiotensin- (1-7) and angiotensin Ii in isolated rat portal vein
Petrescu, G.; Gurzu, B.; Slătineanu, S.M.; Costuleanu, M.; Costuleanu, N.
Revista Medico-Chirurgicala a Societatii de Medici Si Naturalisti Din Iasi 107(1): 102-107
2003
ISSN/ISBN: 0048-7848 PMID: 14755978 Document Number: 554591
Our preliminary data show for the first time the interaction between angiotensin-(1-7) (Ang-(1-7)) and angiotensin II (Ang II, 10 nM) in isolated rat portal vein. Very low concentrations (10 nM) of Ang-(1-7) have marked functional antagonizing effects on Ang II-induced contractions. High concentrations of Ang-(1-7) (1-10 mM) do not affect the effects of Ang II. The effects of low concentration Ang-(1-7) might be associated to the interaction with Ang-(1-7) specific receptors and the own contractile effects (approximatively 28%) at high concentrations might be assign to the interaction with angiotensin specific receptors AT1. But, the lack of effects of Ang-(1-7) high concentrations on Ang II-induced contractions hardly might be associated to the interaction with AT1 receptors. Although losartan was entirely blocking the Ang-(1-7) effects, there is in the literature a series of data showing that Ang-(1-7) specific receptors (or a subtype of Ang-(1-7) receptors) might be sensible (with possible high affinity) to losartan. Additional experiments are thus necessary to further clarify these interactions.