VASODILATIVE EFFECT OF ADRENOMEDULLIN IN ISOLATED ARTERIES OF THE DOG

Adrenomedullin is known to induce profound hypotension in vivo, but th e direct effect of this peptide on isolated arteries has not been demo nstrated. This study estimated the vasodilative effects of adrenomedul lin in comparison with those of calcitonin gene-related peptide (CGRP) in basilar, mesenteric, coronary, renal and femoral arteries isolated from the dog. Adrenomedullin (3 to 100 nM) and CGRP (1 to 30 nM) indu ced concentration-dependent relaxation of these arteries with and with out endothelium, and the relaxing effects were slightly greater in end othelium-intact arteries than in denuded ones. The vasodilative potenc y of adrenomedullin relative to CGRP was smaller in the femoral artery than in basilar, mesenteric, coronary and renal arteries.