Pre-Emptive Analgesic Effects of Tramadol, St. John's Wort, and Panax Ginseng Extract in Mice

Abstract

Aim: Pre-emptive analgesia, has been popularised by demonstration of its important decremental effects on the severity and duration of pain. Our aim was to evaluate the pre-emptive analgesic efficacies of St. John's Wort (SJW), Panax ginseng (GNS), and tramadol (TRM) by constructing a surgical pain model in rats. Material and methods: Ninety-six rats were divided into three groups: preoperative, postoperative, and control. The preoperative group received the study drug or placebo (10 ml/kg physiological saline via the intraperitoneal route) one hour before and two hours after the incisions. The postoperative group was given the study drug or placebo 2 hours after the incisions. Finally, the placebo was administered to the control group one hour before and two hours after the incisions. The drugs (25, 50, and 100 mg/kg SJW; 100 mg/kg GNS; and 20 mg/kg TRM) were administered intraperitoneally. Their analgesic efficacies and motor activities were evaluated using a hot-plate test and locomotor activity tests. Results: The locomotor activities of SJW were lower than those of the control and TRM groups. The study drugs were compared among groups, and preoperative hot-plate test latencies following administration of 100 mg/kg SJW were longer than those of the postoperative group. When compared irrespective of the groups, the hot-plate latencies of SJW 100 mg/kg, GNS, and TRM were longer than that of placebo. Conclusions: In our study, SJW 100mg/kg, GNS, and TRM demonstrated an antinociceptive effect in the hot-plate test in mice, while the drugs apart from TRM suppressed locomotor activity. In addition, SJW, GNS, and TRM did not manifest pre-emptive analgesic efficacy in this study.