ADRENOMEDULLIN, A NEWLY DISCOVERED HYPOTENSIVE PEPTIDE, IS A POTENT BRONCHODILATOR

The present study was designed to examine the effect of adrenomedullin (AM), a novel vasorelaxant peptide originally isolated from human pheochromocytoma, on histamine-or acetylcholine-induced bronchoconstriction in anesthetized guinea pigs in vivo. AM significantly inhibited acetylcholine-induced bronchoconstriction in a dose-dependent fashion. AM also significantly inhibited histamine-induced bronchoconstriction, but 10(-10) M AM had no significant inhibitory effect on this response. We also found that AM induced a long-lasting bronchodilator response, while isoproterenol induced transient bronchodilation. These preliminary findings suggest that AM may play important roles in airway function. (C) 1994 Academic Press, Inc.