GINSENOSIDES EVOKE ENDOTHELIUM-DEPENDENT VASCULAR RELAXATION IN RAT AORTA

1. Ginsenoside(10-100 mg/kg, i.v.) lowered blood pressure in a dose-de pendent manner in rats. 2. Ginsenoside (10(-5)-3 x 10(-4) g/ml) relaxe d the aorta after contractions were induced by 10(-6) M phenylephrine in the aorta with endothelium but not in that without endothelium. 3. The relaxation induced by ginsenoside was attenuated by 3 x 10(-7) M m ethylene blue (MB) and 10(-4) M N-G-monomethyl-L-arginine (L-NMMA) but not inhibited by 10(-5) M indomethacin. 4. Ginsenoside (10(-4) g/ml f or 2 min) increased the accumulation of cGMP in rings with endothelium . L-NMMA and MB inhibited the accumulation of cGMP induced by ginsenos ide. 5. These data suggest that vascular relaxations induced by ginsen oside are mediated by release of endothelium-drived nitric oxide which enhances the accumulation of cGMP.