Angiotensin II induced venoconstriction in normotensive and hypertensive rats: study of action mechanisms, localization and expression of AT1 and AT2 receptors. / Venoconstrição induzida por angiotensina  II em ratos normotensos e hipertensos: estudo de mecanismos de ação, localização e expressão de receptores AT1 e AT2.

AUTOR(ES)
DATA DE PUBLICAÇÃO

2007

RESUMO

In this study we have evaluated and characterized the effect of Ang II in the isolated perfused mesenteric venular bed (MVB) and portal vein rings (PVR) of SHR and wistar rats. Vascular reactivity to Ang II was studied in the absence and presence of different antagonists to elucidate the mechanisms involved in Ang II-induced venoconstriction. Our results suggest that Ang II induces venoconstriction by activation of AT1 and AT2 receptors in wistar and AT1 receptor in SHR. These venoconstriction seems to be counterbalanced by B2 receptor in both species. NO might contribute to this effect in wistar and COX metabolites in SHR. There is a decrease in Ang II induced venoconstriction in PVR of SHR that might be related to the decrease of protein expression of AT2 receptor. These results indicate different mechanisms of regulation of venous tonus of the SHR and wistar rats induced by Ang II that can be relevant in the control of the venous return and cardiac output.

ASSUNTO(S)

sistema venoso. sistema renina angiotensina renin angiotensin system venous system. angiotensin ii hypertension angiotensina ii hipertensão

ACESSO AO ARTIGO

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