Vasopressin-induced vasoconstriction is dependent on MAPK(erk1/2) phosphorylation

To investigate the involvement of the mitogen-activated protein kinase (MAPK) family of extracellular signal-regulated kinase (ERK) 1 and 2 (MAPK(erk1/2)) in the vasopressin-mediated vasoconstriction in the rat aorta. Vasopressin-induced vasoconstriction was measured in isolated rat thoracic aortae in the presence or absence of MAPK(erk1/2) kinase (MKKmek1/2) inhibitors. Thereafter the MAPK(erk1/2) phosphorylation in the rat aorta was quantified using Western blot analysis. Vasopressin (1-300 nm) induced a concentration-dependent vasoconstriction, which could be inhibited concentration dependently by the selective MKKmek1/2 inhibitors, PD 98059 (10 and 100 muM) and U 0126 (10 and 100 muM). Western blot analysis revealed a 2.7 +/- 0.6-fold increase in the MAPK(erk1/2) phosphorylation induced by vasopressin (300 nm). This phosphorylation could be dose dependently prevented by both PD 98059 (100 muM) and U 0126 (10 and 100 muM). These results indicate that vasoconstriction induced by vasopressin is partly regulated by the MAPK(erk1/2) pathway