EFFECTS OF INTRAVENOUS INJECTION OF STRYCHNINE ON ANALGESIC EFFECT OF KETAMINE

[Objective]To discuss the relationship between glycine receptor and analgesic effect of ketamine.[Methods]The changes of pain threshold in hot-plate test and writhing test were examined,and the effects of intravenous injection of strychnine at different doses on the rats injected with ketamine were observed.[Results]Intraperitoneal injection of Ket(10 mg/kg)had no effect on pain threshold in hot-plate test(P﹥0.05),but intraperitoneal injection of Ket(20 mg/kg or 40 mg/kg)increased the HPPT of the rats(P﹤0.05);intraperitoneal injection of Ket(10 mg/kg)had no effect on writhing times(P﹥0.05),whereas intraperitoneal injection of Ket(20 mg/kg or 40 mg/kg)decreased writhing times(P﹤0.05).Intravenous injection of Strychnine(0.25 μg)had no effect on the HPPT of the rats injected with Ket(40 mg/kg)(P﹥0.05),while intravenous injection of Strychnine(0.5、0.75、1.0 μg)decreased the HPPT(P﹤0.05);and intravenous injection of Strychnine(0.25、0.5、0.75、1.0 μg)had no effect on writhing times(P﹥0.05).[Conclusions]Analgesic effect of ketamine in hot-plate test and writhing test are different,which indicates that the former may involve glycine receptor while the later has little relation with glycine receptor.