Aim To observe the analgesic effect of oxymatrine(OMT)and its mechanism.Methods A peripheral mononeuropathy was produced in adult mice by placing loosely constrictive ligatures around the common sciatic nerve.The antinociceptive effects of the OMT were assessed in mechanical allodynia and cold allodynia tests.The CAMKII inhibitor KN-93 and AIP were adopted to investigate the influence of OMT on the analgesic effect and analyze its analgesic mecha-nisms.Western blot was used to evaluate the expres-sions of tCaMKII and pCaMKII protein.Results The intraperitoneal administration of OMT (1 60,80 mg· kg -1 )increased the paw withdrawal threshold in the
mechanical allodynia test (P <0.05 ),OMT (1 60, 80,40 mg·kg -1 ,ip)remarkably decreased the paw lifts in the cold allodynia test (P <0.05).Ith KN-93 (1 .25 μg/site),AIP (0.02 μg/site)significantly en-hanced the analgesic effect of OMT (35 mg·kg -1 ) (P <0.01 ).Protein expression of pCaMKII was de-creased by OMT(1 60 mg·kg -1 ).Conclusion OMT has significant protective effects on chronic constriction injury(CCI)in mice,and the effective mechanism of OMT inhibits the expression of CaMKII receptor.