[Comparative study on the analgesic effect of electroacupuncture at "Sanyinjiao" (SP 6), "Hegu" (LI 4) and "Xuehai" (SP 10) in dysmenorrhea rats].

OBJECTIVE: To observe and compare the analgesic effect of electroacupuncture (EA) at "Sanyinjiso" (SP 6), "Hegu" (LI 4) and "Xuehai" (SP 10) in dysmenorrhea rats so as to investigate the functional specificity of acupoint. METHODS: One hundred SD female rats aged three-month-old in the diestrus examined by the vaginal smear screening were randomly divided into a saline group, a model group, a Sanyinjiao (SF 6) group, a Hegu (LI 4) group and a Xuehai (SF 10) group, 20 rats in each group. The rats in the last four groups were given Estradiol Benzoate combined with Oxytocin to prepare the models of dysmenorrhea and in the saline group were given the same dose of saline. Last three groups were treated with electroacupuncture (EA) at Sanyinjiao" (SF 6), "Hegu" (LI 4) and 'Xuehai" (SF 10) respectively. The writhing behaviors of the rats in each group were observed within 20 min performing electroacupuncture from the start of the pain and the waveforms of uterine contraction were recorded. RESULTS: In terms of the writhing behaviors, the writhing latency in the Hegu (LI 4) group was extended significantly (P < 0.05, P < 0.01) and the writhing numbers in the Hegu (LI 4) group were decreased significantly (both P < 0.05) as compared with those in the Sanyinjiao (SF 6) group and in the Xuehai (SF 10) group. In terms of the waveforms of uterine contraction, compared with that in the model group, the amplitude and the activity of uterine contraction in both Sanyinjiao (SF 6) group and Hegu (LI 4) group were decreased significantly (all P < 0.05), and with no significant difference between the Xuehai (SF 10) and the model group (P > 0.05). CONCLUSION: For comprehensive assessment of the analgesic effect of electroacupuncture at different acupoints by using the writhing behaviors and the waveforms of uterine contraction, "Hegu" (LI 4) is the best, "Sanyinjiao" (SP 6) is the next and "Xuehai" (SP 10) is the third. showing a relatively functional specificity of the acupoint.