CONTRACTILE EFFECTS OF ANGIOTENSINS ARE INDEPENDENT OF RECEPTORS INTERNALIZATION IN RAT AORTA

-Arrestins-mediated signaling downstream of seven transmembrane receptors is a relatively new paradigm for signaling by these receptors. The inhibitors of AT1 receptor internalization we tested, that means nigericin, concanavalin A and monensin, did not significantly alter the contractions induced by Ang II in the rat aortic smooth muscle preparations. The same effects we obtained also when we used as agonists Ang I, Ang III and Ang IV. Thus, the contractile effects induced by angiotensin peptides administered in the rat aortic smooth muscle preparations are independent of their receptors internalization. Since -arrestins are mediating G-protein independent signaling via AT1 receptors their involvement in the contractile effects of angiotensin peptides must be further explored.