Hs. Kim et al., Effects of the ginsenosides Rg(1) and Rb-1 on morphine-induced hyperactivity and reinforcement in mice, J PHARM PHA, 50(5), 1998, pp. 555-560
Recent studies have demonstrated that ginseng saponin inhibits the hyperact
ivity and conditioned place-preference response induced by psychostimulants
and opiates. This seems to occur by direct or indirect modulation of dopam
inergic activity. However, it is not known which components of ginseng sapo
nin are active. These experiments were conducted to determine the effects o
f the ginsenosides Rb-1 and Rg(1), major components of the protopanaxadiol
and protopanaxatriol fractions of ginseng saponin, on morphineinduced hyper
activity and conditioned place-preference.
Morphine-induced hyperactivity, but not apomorphine-induced climbing behavi
our, was inhibited by both Rb-1 and Rg(1). These findings confirm the hypot
hesis that ginsenosides modulate catecholaminergic activity preferentially
at pre-synaptic sites. Morphine-induced conditioned place-preference was in
hibited by Rg(1), but not by Rb-1. It has previously been shown that at low
doses Rb-1 and Rg(1) are equally effective at inhibition of catecholamine
secretion at the pre-synaptic site, but that at high doses Rg(1) is a more
effective inhibitor. This observation might explain our finding that morphi
ne-induced conditioned place-preference was inhibited by Rg(1) only.
Our findings suggest that Rg(1), a component of ginseng saponin with approp
riate activity, might be a useful agent for prevention and treatment of the
adverse effects of morphine.