Abstract: Objective To investigate the analgesic effect of Gabapentin combined with Morphine on neuropathic pain of rabbit,and the effects on inflammatory cytokines TNF and IL-6.Methods Twenty rabbits with successfully established neuropathic pain were randomly divided into four groups:saline(NS),Gabapentin(G),Morphine(M) and combination of Gabapentin and Morphine(MG).Animals in each group were given the appropriate drug by gastric gavage.Before and after administration,the behavioral changes of the rabbits were observed,while the neurotransmitters 5-HT and NE,inflammatory cytokines TNF-α and IL-6 in serum were measured by ELISA.Result 1.Behavioral change:after administration,the spontaneous pain of rabbits in groups M,G and MG had various degree of improvement,which appeared earliest in MG group,while the G group appeared earlier than M group.The NS group had no significant change.2.Neurotransmitter change:the neurotransmitters in serum reduced in Groups G,M and MG after administration(P<0.05),which appeared earlier in group MG than that in group M and G.Group NS had no significant change.3.Inflammatory cytokines change:after administration,the inflammatory cytokines in serum decreased in groups G,M and MG,which appeared earlier in group MG than that in group M and G.Group NS had no significant change.Conclusions The synergistic effect of Gabapentin and Morphine can effectively relieve neuropathic pain in rabbits,and can reduce the expressions of inflammatory cytokine TNF and IL-6.The analgesic efficacy of Gabapentin combined with Morphine is better than that by using Gabapentin or Morphine alone.

Key words: Neuropathic pain, Gabapentin, Morphine, Cytokines