The mechanisms of vasorelaxant effect of leptin on isolated rabbit aorta

In the present study, we analysed the effects of leptin on rabbit aorta and the mechanisms underlying these effects. Leptin (10(-12)-10(-9) m) induced concentration-dependent relaxation in intact rabbit aorta rings precontracted with phenylephrine (10(-6) m). Removal of endothelium abolished the effects of leptin. Pretreatment of rings with N(omega)-nitro-l-arginine methyl ester (10(-4) m 20 min) or catalase (1200 U/mL 20 min) significantly reduced the relaxant response to leptin when compared with the control group. The incubation of brefeldin A (3.5 x 10(-5) m 90 min), indomethacin (10(-5) m 20 min), tetraethylammonium (10(-4) m 20 min), and glibenclamide (10(-5) m, 20 min) did not affect the leptin-induced vasodilation. These results suggest that leptin relaxes the rabbit aorta. The relaxation is mediated by endothelium-derived nitric oxide and hydrogen peroxide.