Human urotensin-II is a potent spasmogen of primate airway smooth muscle

The contractile profile of human urotensin-II (hU-II) was examined in prima te airway and pulmonary vascular tissues, hU-II contracted tissues from dif ferent airway regions with similar potencies (pD(2)s from 8.6 to 9.2). Howe ver, there were regional differences in the efficacy of hU-II, with a progr essive increase in the maximum contraction from trachea to smaller airway r egions (from 9 to 41% of the contraction to 10 mu M carbachol). hU-II poten tly contracted pulmonary artery tissues from different regions with similar potencies and efficacies: pD(2)s=8.7 to 9.3 and maximal contractions= 79 t o 86% of 60 mM KC. hU-II potently contracted pulmonary vein preparations ta ken proximal to the atria, but had no effect in tissues from distal to the atria. This is the first report describing the contractile activity of hU-I I in airways and suggests that the potential pathophysiological role of thi s peptide in lung diseases warrants investigation.