Effect of urotensin Ⅱ on nitric oxide synthese/nitric oxide pathway in rat aorta / 北京大学学报(医学版)

ABSTRACT

Objective: To study the effect of urotensin(U Ⅱ) on nitric oxide synthase(NOS)/nitric oxide(NO) system in rat aorta. Methods: The aortic slices were incubated in vitro. The medium nitrite content, vascular NOS activities and cGMP content were measured. Results: After incubation of aorta for 1.5－3.0 h, UⅡ(10－9－10－7　mol*L－1) increased nitrite production ( 14.8%－80.9%, P<0.01) in dose-dependent manner. U Ⅱ significantly stimulated the total NOS activities, mainly activated constitutive NOS (P<0.05 or P<0.01), however, the inducible NOS activities were not altered (P>0.05). Incubation of aortic slices with U Ⅱ (10－9－10－7 mol*L－1) increased vascular cGMP content in dose-dependent manner. Co-incubation vascular tissue with U Ⅱ and　GN-L-nitro-arginine, an inhibitor of NOS, obviously inhibited the U Ⅱ-induced NOS activation, NO production and cGMP formation. Conclusion: The results suggest that U Ⅱ can activate the vascular NOS/NO pathway, increasing tissue NO production and cGMP content.