针刺信息激活中枢神经系统各个水平的抗痛结构以及通过下行抑制系统来对抗伤害性传入冲动而产生镇痛效应已有许多实验研究资料。电针对外周神经的作用如何

目前资料不多。有人观察到电针刺激对外周神经有压抑作用

但多数为“同纤维”效应

即A纤维被兴奋时

动作电位A波受压抑。少数实验中也出现“异纤维”效应。即仅有A类纤维被兴奋但压抑效应却可涉及C波。还有人观察到电针大鼠“足三里”、“环跳”对It was known that the anti-pain organization of each level in central nerve system could be activated by acupuncture. But it isn't quite clear if the inhibitory effect of acupuncture can appear on peripheral afferent C fibre. We observed that acupuncture at right side made the amplitute of the C potential of left common peroneal nerve(CPN)decreased. The purpose of this work isto observe the effect of acupuncture on a- fferent impulses of CPN at opposite side after cutting off the relationship between centre and periphery

and go further into the priciples governing acupuncture anesthesia and the effect of distant acupoints. In the present experiments

the C potential wes strictly distingiushed by measuring conduction velocity of nerve

changing the distance of CPN between stimulative and recording electrodes

paralyzing the animal

cu- tting off the distal end of CPN and injecting procaine into the nerve. Right acupoints "Sanyinjiao" and "Yinlingchuan" were stimulated by EA in rabbits

the A potential of the complex action potential induced by ele- ctric stimulation on left CPN didn't show the significant change

P>0.25

but the C potential showed the inhibitory effect(n=13). It showed that the decrease of C potential was with significant difference at the weak EA(5.7 V) for 5 min and 10 min after ceasing EA

P<0.05 (n=25); at strong EA (45V) for 5 min and 10 min after ceasing EA

P<0.001(n=9). However. the amplitude of C potential increased after that sciatic nerve was cut. At this condition

neither A potential nor C potential showed the inhibitory effe-ct by EA(n=15). The results suggest that the effect of the distant acupoints are perfo- rmed by resisting the trasmission of peripheral noxious afferent via the descending inhibitory system. While peripheral nerve was separated from centre

the inhibitory effect of EA on peripneral noxious afferent of oppo- site side disappeared. The amplitude of C wave increased after cutting off sciatic nerve

it indicates that the high centre exerts a tonic inhibitory control on the noxions afferent of peripheral nerve in normal.