crocin-induced endothelium-dependent relaxation in isolated rat aorta

Background: crocin, an active ingredient of saffron, has been found to possess hypotensive effects. objectives: the aim of this study was to evaluate the mechanism of vasodilatory effects induced by crocin on isolated rat aorta. methods: to study the vasodilatory effects of crocin (0.1, 0.2, 0.4 and 0.8 m), isolated rat thoracic aorta rings were contracted by 10^-6 mphenylephrine (pe) or 80m mof kcl. to assess the role of nitric oxide in mechanism of relaxation, induced by crocin, aortic rings were incubated by l-ng-nitroarginine methyl ester (l-name: 10^-6 m) for 20 minutes. furthermore, the relaxant effect of crocin was evaluated both in intact and denuded endothelium aortic rings. results: crocin induced relaxation in endothelium-intact aortic rings precontracted with pe in a concentration dependent manner yet not in kcl precontracted aortic rings. the relaxant activity of crocin was abolished by incubation of aortic rings with l-name. in addition, the endothelium removal inhibited the relaxant activity of crocin. conclusions: this study indicated that relaxant activity of crocin is mainly mediated through an endothelium-dependent mechanism.