MANUAL ACUPUNCTURE PRODUCES LONG TERM INHIBITION OF THE NOCICEPTIVE TRANSMISSION TO WIDE DYNAMIC RANGE NEURONS IN THE SPINAL CORD OF THE RAT

Acupuncture,includingelectricalandmanualacupuncture,hasb'enwidelyusedinclinicalandexperimentalpracticetore-lievepain.Althoughbothproceduresseemtobeeffectiveinproducinganalgesi-ac1.3.7～9.l2.16～1B,,thephysiologicalmecha-nismsunderlyingeitherformofacupunc-ture,especiallyfortraditionalmanualacupuncture,thathasalonghistoryofef-fectivenessandhasbeenusedmorewide-ly,arestilluncleart14).Itshouldbenotedthatlittleattentionhasbeenpaidtoinves-tigationofthephysiologicalmechanismsofmanualacupuncturewhichha…

MANUAL ACUPUNCTURE PRODUCES LONG TERM INHIBITION OF THE NOCICEPTIVE TRANSMISSION TO WIDE DYNAMIC RANGE NEURONS IN THE SPINAL CORD OF THE RAT

singe unit discharge recordings were made from 42 WDR neurons in spinal dorsal horn in the rat. These neurons could he driven by electrical stimull activiting innocuous and noxious afferent fibres in the ipsilateral plantar nerve. Traditional manual acupuncture delivered at the local acupoints Zusanli, Chengshan, Kunlun and Yongquan induced a strong inhibition or the C-fiber response. in 19 of 42 neurons obtained but did not after the A-fibre response of the neurons. The inhibition of the fibre response outlasted the period of acupuncture for more than 30 min. Neither Anor C-fibre responses in the remaining 23 neurous could be affected by manual acupuncture. These results suggest that the acupuncture stimulation specifically influences nociceptive nociceptive transmission,maybe through a presynaptic action,Furthermore, the fact that the inhibitory effect outlasts the stimulation by more than 30 min indicates that either a neuromodulatory ,presumably peptidergic action is at hand or that a temporary synaptic modification occurs in the spinal dorsal horn.