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.