Abstract: Objective：To investigate the effect of electroacupuncture(EA) on morphine tolerance of rats and on changes of the phosphorylation of transient receptor potential vanilloid subfamily member 1（TRPV1）,which is a member of capsaicin receptor. Method:The 24 healthy male SD rats were randomized into 3 groups (n=8): they were administered respectively intrathecally 10 L saline for group N; 10 g morphine for group M; 10g morphine and 2HzEA on "Zu-San-Li" and "Yang-Ling-Quan" after the first administration of morphine every day for group H.Administration of the three groups were all twice daily for 7days.Mechanical withdrawal threshold (MWT) and thermal paw withdrawal latency (PWL) of rats was examined to evaluate their mechanical hyperalgesia and heat hyperalgesia. Take the L4~5 dorsal root ganglion(DRG) on the 8 day of administration ,and the expression of total TRPV1 and phosphorated TRPV1 in DRG was measured by western-blot.Result: The rats in group M were developed morphine tolerance .2Hz EA can alleviated the formation of morphine tolerance.The expression of total TRPV1 in group M were significantly higher than that in group N and group H,while there's no significant difference between group N and group H.The phosphorylation of TRPV1 in DRG of group M were increased significantly,while the expression of phosphorylated TRPV1 in group H were significantly lower compared with that of group M.Conclusion:2Hz EA has inhibitory effect on morphine tolerance and tolerance-associated thermal hyperalgesia,it may be through the inhibition of phosphorylation of TRPV1 in DRG.

Key words: Electroacupuncture(EA), Morphine tolerance, TRPV1, Phosphorylation, dorsal root ganglion(DRG)