平衡针对人皮层痛觉诱发电位的影响

Effect of Balance Acupuncture on Cortical Pain-evoked Potential in Human Subjects

目的观察平衡针对健康成年人体感诱发电位的影响,探讨平衡针镇痛即时效应的神经电生理机制。方法 20例健康成年人,刺激电极位于受试者内踝后2～3 cm内侧胫后神经皮支分布处,平衡针刺对侧上肢腕部踝痛穴,观察针刺前,针刺即刻,针刺后5 min,针刺后10 min皮层痛觉诱发电位的P40、N45、P60、N75的潜伏期和波幅的变化。结果 P40、N45、P60、N75的潜伏期在针刺即刻明显延长(P<0.01或P<0.05);N45的波幅在针刺即刻、针刺后5 min、针刺后10 min均比针刺前有不同程度的降低(P<0.01);其他3个波的波幅变化不明显。结论平衡针的即刻镇痛效应主要通过对N45的调节而实现。其镇痛作用机制可能与针刺信号阻滞了痛信号的传导并抑制了皮层痛放电神经元的数量有关。

Objective To observe the effect of balance acupuncture on somatosensory evoked potential in healthy adults, and to explore the electrophysiologieal mechanism of real-time analgesic effect of balance acupuncture. Method Twenty healthy adults were included, and stimulation electrodes were placed on the distribution of cutaneous branch of posterior tibial nerve, 2 -3 cm behind the medial malleolus. Balance acupuncture was used for ankle pain point on the contralateral upper limb. The latency period and amplitude of cortical pain-evoked potentials P40, N45, P60, and N75 were observed before acupuncture, immediately after acupuncture, 5 min after acupuncture, and 10 min after acupuncture. Result The latency periods of P40, N45, P60, and N75 were significantly extended immediately after acupuncture （P〈0.01 or P〈0.05）; the amplitude of N45 was reduced markedly immediately after acupuncture and at 5 min and 10 min after acupuncture, compared to that of before acupuncture （P〈0.01）; the amplitudes of the other potentials didn＇t show significant changes. Conclusion The real-time analgesic effect of balance acupuncture is realized through regulating N45. We believe that the analgesic mechanism should be that the acupuncture signal blocks the transduction of pain signal and inhibits the quantity of cortical pain firing neurons.