(A) Alleviation of mechanical allodynia by microglial activation inhibitor, minocycline. Mechanical threshold was tested before and after intraperitoneal (i.p.) injection of minocycline. The mechanical threshold was increased by minocycline (30 mg/kg, i.p.) 30 min after administration and the effect was diminished within 1 hour. ***p < 0.001. (B) P2X7 antagonist, A438079 eliminated mechanical allodynia caused by TIC nerve trauma. Whisker pad mechanical threshold was tested before and after intraperitoneal injection of A438079. The mechanical allodynia was reduced by A438029 (10 mg/kg, i.p.) as early as 30 min after injection. The analgesic effect reached peak at 1h and diminished at 3 h. **p < 0.01, ***p < 0.001. (C) P38 inhibitor, SB203580 reversed the TIC nerve trauma induced mechanical allodynia. Mechanical threshold in the whisker pad was tested before and after intraperitoneal injection of SB203580. The mechanical allodynia was reduced by SB203580 (50 μg/kg, i.p.) starting at 30 min. The maximal analgesic effect persisted for 3 hours. *p < 0.05, **p < 0.01.