Effect of intraperitoneal administered ginseng total saponins on hyperalgesia induced by repeated intramuscular injection of acidic saline in rats

The aim of this study was to assess the antinociceptive activity of ginseng total saponins (GTS) on hyperalgesia induced by repeated intramuscular injections of acidic saline in rats and to examine the mechanisms involved. Rats were injected intraperitoneally with a 0.9% saline vehicle or various doses of GTS after the development of hyperalgesia. Rats were then injected with N-methyl-D-aspartate (NMDA) or naloxone 10min before GTS injection. The mechanical withdrawal threshold (MWT) was assessed with von Frey filaments. The MWT was significantly increased after intraperitoneal injection of 100mg/kg and 200mg/kg of GTS when compared with the MWT after the development of hyperalgesia. Injection of GTS with NMDA showed a significant decrease in the MWT when compared with GTS injection. GTS showed an antinociceptive activity against chronic muscle-induced pain, and the effect of GTS may be mediated by NMDA.