Abstract:Objective: To investigate the antinociceptive effects of Riluzole administered intraperitoneally in three hyperalgesia model of mice. Methods: Antinociceptive tests in C57BL mice were investigated with formalin test、acetic acid induced writhing test and tail-immersion test. The effects of intraperitoneally Riluzole 2 mg/kg、4 mg/kg and 8 mg/kg on the pain threshold were observed. Result: We found that i.p. treatment with Riluzole (4 mg/kg and 8 mg/kg) blocked the second phase flinching behavior compared with vehicle (P < 0.05), but not during the first phase in the formalin test. In addition to the formalin test, Riluzole at different dose (from 2 to 8 mg/kg) attenuated acetic acid induced writhing response when compared to vehicle group (P < 0.05). In the tail-immersion test, Riluzole at the highest dose (8 mg/kg) caused significant increase in tail flick response latency as compared to vehicle animals or compared with Baseline (P < 0.05). Conclusion: Our results suggest that glutamate release inhibitor Riluzole can attenuate nociceptive behavior and has differrent antinociceptive characteristic according to the various pain models.