We previously reported that adrenomedullin (AM), a potent vasodilator peptide discovered in pheochromocytoma cells, stimulates nitric oxide (NO) release in the rat kidney. To further investigate whether the NO-cGMP pathway is involved in the mechanisms of AM-induced vasodilation, we examined the effects of E-4021, a cGMP-specific phosphodiesterase inhibitor, on AM-induced vasorelaxation in aort...