Effects of Ginseng Total Saponins on the Antinociception and the Tolerance Development of U-50,488H

These studies were performed to investigate the acting sites of ginseng total saponins (GTS) on the U-50, 488H-induced antinociception and the inhibitory effect of the development of tolerance to U-50, 488H-induced antinociception by GTS were studied. The U-50, 488H-induced antinociception was ntagonized in mice pretreated with GTS intraperitoneally, intracerebrally. These antagonisms were reversed by the pretratment iwth a serotonin precursor, 5-hydroxytrypophan (5-HTP), but not with a noradrenaline precursor, L-dihydroxyphenylalanine (L-DOPA). However, the intraplantar sites. On the other hand, GTS inhibited the development of tolerance to U-50, 488H-induced antinociception was reversed by pretreatment with 5-HTP, but not with L-DOPA. Therefore, the antagonism of U-50, 488H-induced antinociception and the inhibition of the development of tolerance to U-50, 488H-induced antinociception and the inhibition of the development of tolerance to U-50, 488H-induced antinociception by GTS are dependent on serotonegic mechanisms.