Effects of Ipsilateral and Contalateral Stimulation of Peripheral Nerve on Flexion Reflex in Cats

동측(ipsilateral) 및 대측(contralateral) 말초신경자극이 굴근반사에 미치는 영향의 비교연구

It is well known that the acupuncture has been used effectively for the relief of certain types of pain. Although the precise mechanism of action of acupuncture analgesia is unknown, it is generally accepted that their analgesic properties are related to the activation of endogenous opiate system in central nervous system. And it is suggested that pain-relieving properties of acupunture may be related to a stimulation of peripheral nerve underlying the acupuncture point on the skin. However, the efficacy of acupuncture has no relationship between the site of pain and the acupuncture point. Consequently, the present study was undertaken to investigate electroacupuncture analgesia in relation to the site of peripheral nerve stimulation. Cats were decerebrated ischemically and the flexion reflex as an index of pain was elicited by stimulating the sural nerve (20V, 0.5 msec duration) and recored as a compound action potential from the nerve innervated to the posterior biceps femoris muscle in the ipsilateral hindlimb. Bilateral common peroneal nerve and contralateral superficial radial nerve were selected as the site of peripheral nerve stimulation. For the stimulation of peripheral nerve, a stimulus of 20 V intensity, 2 msec-duration and 2 Hz-frequency was applied for 60 min respectively. The results obtained are summarized as follows: 1) Both stimulation of contralateral common peronal nerve and contralateral superficial radial nerve did not change the flexion reflex and there were no significant differences between them. 2) Stimulation of ipsilateral common peroneal nerve markedly depress the flexion reflex, the effect being reversed by naloxone application. These results suggest that stimulation of ipsilateral common peroneal nerve has the analgesic effect but both stimulation of contralteral common peroneal nerve and contralateral superficial radial nerve to the pain site where flexion reflex was elicited have no analgesic effect.