Effects of ginsenosides on release of [3H]norepinephrine from rat vas deferens and portal vein.

The effects of ginsenosides (G) on the release of [3H]norepinephrine ([ 3H]NE) from the isolated rat vas deferens (RVD) and portal vein (RPV) preloaded with [3H]NE were studied, G (100 micrograms/ml) did not affect the spontaneous or high potassium (H-K+, 60 mmol/L)- and tyramine (Tyr 10 mumol/L)-evoked release of [3H]NE, but obviously blunted the phentolamine (Phe 10 mumol/L)-induced increase in [3H]NE release from RVD and enhanced the isoprenaline (Iso 0.1 mumol/L)-augmented [3H]NE release from RPV evoked by H-K+. It is still not known whether G can bind with adrenoceptors. We infer that G may act as a modulator in sensitizing both presynaptic alpha 2- and beta-receptors.