EFFECT OF ELECTROACUPUNCTURE ON DISCHARGES OF NEURONS EXCITED AND NEURONS INHIBITED BY NOXIOUS STIMULATION RECORDED SIMULTANEOUSLY IN N.PARAFASCICULARIS AND N.CAUDATI OF RATS

Coupled recordings of discharges in n.parafascicularis and n.caudati weremade in 44 rats in order to observe their responses to the noxious stimulation ofthe sciatic nerve.The effects of electroacupuncture at point“Zusanli”on dis-charges of 81 pairs of neurons were studied.The results were as follows:1.The electrical activities of neurones excited and neurones inhibited bynoxious stimulation could be obtained simultaneously in n.caudati of rats andthe firing patterns of these two types of neurones were similar to those found inn.parafascicularis.2.Noxious stimulus could bring about contemporaneous excitation of,neu-rones in n.parafascicularis and n.caudati,or simultaneous inhibition of neuronesin both nuclei,or excitation of certain neurones in one nucleus and inhibition ofneurones in the other.3.Electroacupuncture of“Zusanli”could release the electrical activitiesfrom inhibition by noxious stimulation in some neurones,nociceptive dischargesof others in both nuclei at the same time.It is concluded that noxious stimulus can affect the neuronal discharges ofneurones in n.parafascicularis and n.caudati concomitantly,while electroacu-puncture of“Zusanli”can change the activities of two kinds of neurones(excitedor inhibited by noxious stimulation)in an opposite way.