GINSENOSIDES INDUCE DIFFERENTIAL ANTINOCICEPTION AND INHIBIT SUBSTANCE-P INDUCED-NOCICEPTIVE RESPONSE IN MICE

Ginsenosides are main pharmacoactive molecules of ginseng. The antinoc iceptive activity of ginsenosides after intrathecal (i.t.) injection w as examined in formalin test. We also investigated the effects of gins enosides on substance P (SP) induced-pain behaviors by i.t. treatment using mice. Pretreatment of ginsenosides by i.t. induced the inhibitio n of biting and licking of hind paw injected with 1% formalin with dos e-dependent manner. The ED50 was 23 (19-28, 95% C.I.) mu g/mouse for a cute phase and 15 (9-23, 95% C.I.) mu g/mouse for tonic phase. Interes tingly, cotreatment of ginsenosides with SP also inhibited SP-induced pain behaviors (scratching, licking or biting of hind portion of body) with dose-dependent manner. The ED50 for the inhibition of SP-induced pain behavior by ginsenosides was 30 (11-85, 95% C.I.) mu g/mouse. Th ese results suggest that ginsenosides have antinociceptive activity in formalin test and this effect is due to blocking of SP-induced nocice ptive information to postsynaptic site(s) at the spinal level. (C) 199 8 Elsevier Science Inc.