Relationship of urotensin I induced vasodilatory action in rat thoracic aorta to Ca2+ regulation.

摘要: The relaxant effects of the synthetic fish neuropeptide urotensin I were examined in helical strips rat aorta. In K+-depolarized aorta strips, and verapamil competitively inhibited Ca2+-induced contractions. Urotensin relaxed, a concentration-dependent manner, contraction produced by Ca2+ ionophore A23187, whereas had no effect on this contraction, even at concentration 10(-5) M. absence presence extracellular Ca2+, both components contractions elicited norepinephrine or II, another neuropeptide. Verapamil reduced only II induced with little change Ca2+-free buffer. relaxation response aortic contracted 40 mM KCl was enhanced pretreatment papaverine forskolin. Pretreatment dibutyryl cAMP did not significantly alter action I. endothelial cells to These results suggest that antagonizes (or) mobilization intracellular Ca2+.