不同频率电针对下肢胫后神经体感诱发电位痛成分P_(250)—N_(350)的影响

目的 :观察不同频率电针穴位的镇痛作用规律。方法 :采用电刺激正常人下肢胫后神经获得痛相关成分P2 50 —N350 复合波作为反映疼痛的客观指标 ,观察不同频率电针穴位对痛相关成分P2 50 —N350 波幅、潜伏期变化的影响。结果 :2Hz组针中 1 0、2 0minP2 50 —N350 波幅明显降低 ,差异显著 ,分别为P <0 0 1、P <0 0 0 1 ;40Hz组针中 2 0minP2 50 —N350 波幅明显降低 ,差异显著 ,P <0 0 0 1 ;2Hz、40Hz组针后波幅仍维持较低水平 ,差异显著 ,分别为P <0 0 0 1、P <0 0 1。结论 :2Hz、40Hz电针对SEPS 皮层痛成分有明显的抑制效应 ;针后具有强而持久的后效应

Effects of Different Frequency of Electroacupuncture on Pain Components of Cerebral Somatosensory Evoked Potentials Induced by Tibial Nerve Stimulation in Healthy Subjects

Objective: To observe the regularities of the analgesic effect of electroacupuncture (EA) at different frequencies. Methods: A total of 29 cases of healthy volunteer subjects were randomly divided into control group (n=10), 2 Hz-EA group (n=10) and 40 Hz-EA group (n=9). Cerebral somatosensory evoked potential (SEP) was recorded by using NeuropacR-II recorder following electrical stimulation (a tolerable strength) of the right posterior tibial nerve (medial side of the ankle). EA ( 2 Hz, 40 Hz, 2～4 V, for 20 min) was applied to right Zhibian (BL 54) and Ciliao (BL 32). The P 250-N 350 of complex waves of SEP was regarded as the objective index to reflect pain. Results: In 2 Hz-EA group, during EA, the amplitude values of P 250-N 350 declined significantly at 10 min and 20 min (P<0.01, P<0.001), while no striking changes of the latency were observed (P>0.05). Such is the case in 40 Hz-EA group, additionally, during EA stimulation, the patients responded with pain-relief to a certain degree. Twenty minutes after cease of EA, the amplitude values of P 250-N 350 of 2 Hz and 40 Hz groups still remained rather low level (P<0.01,0.001, vs 10 min of EA), suggesting a post-effect of EA in analgesia. Conclusion: 1) Both 2 Hz and 40 Hz EA have an obvious inhibitory effect on the pain component of SEP induced by tibial nerve stimulation; and 2) there is an apparent after effect of analgesia from 2 Hz and 40 Hz EA.