不同频率电针对外周神经中各类神经纤维兴奋性的影响

<正> 我们过去的研究证明,电针兴奋的神经纤维愈细、镇痛作用愈强。并发现高频电针(45～100次/秒)的镇痛作用不如低频电针(2～5次/秒)效果好。推论其可能的原因之一是由于高频电针刺激可使各类纤维的兴奋性降低,在外周神经上压抑了镇痛冲动的传入。为了论证这一推论,本工作观察了不同频率电针刺激对各类神经纤维兴奋性的影响,为电针镇痛选择适宜的刺激频率及强度提供神经生理学的依据。

EFFECTS OF ELECTROACUPUNCTURE STIMULATION(EAS)OF DIFFERENT FREQUENCIES ON THE EXCITABILITY OF FIBRES OF VARIOUS GROUPS

The effects of EAS of different frequencies on the excitability of various groups in peroneus nerve were studied in rabbits,using standard electro-quantity(a)as the quantitative indices of excitability and consu- lting change of conduction velocity,magnitude and duration course of action potential.The results showed that the excitablity reduction of fibres of various groups is evoked by different frequencies of EAS. Each of fibres of these groups possesses its own critical frequency of EAS,that is,the fibres of group Ⅰ are 200 Hz,the fibres of group Ⅱ are 100 Hz,the fibres of group Ⅲ are 10 Hz and the fibres of group Ⅳ are 5 Hz.Thus,the neurophysiological basis of the selection of the best current intensity and frequency of EAS is provided in electroacupuncture analgesia.It is suggest 1.if a weak current intensity is used to excite the fibres of groups Ⅰ and Ⅱ,the EAS frequency should be less than 100 Hz;2.if a middle current intensity is used to excite the fibres of group Ⅲ,the EAS frequency should be less than 10 Hz;and 3.if a strong current intensity is used to excite the fibres of group Ⅳ,the EAS frequency should be less than 5 Hz.In the above conditions,the safety factor of fibres of various groups would be assured and the excitability of nereve fibres will not be reduced.