The chronic microelectrode techniques were carried out on 23 cats. The response of a single unit activity of bulbar medulla and the behavior respo nses were recorded when the intenstive stimulus applied to the central end of splanchnic nerve. Among 128 neurons from 18 cats

the frequency of neuronal discharges was increased in 100 units (about 78.1%)

and decreased in 27 units (abo- ut 21.1%). The pain response

increasing abdominal muscle contration and the pupil dilation occurred concomitantly. with the change of neuronal di- scharges. The behavior responses of entire body

however

were elicited when the intensity of noxious stimulation was increases signficantly. In most conscious cases

the changes of bulbar unit discharge

either increasing or decreasing

were depressed by electroacupuncture

but there was no significant change in the behavior responses arised from the spla- nchnic stimulus. It is therefore concluded that the depression of unit discharge in ce- ntral nervous system

in general

may serve as an analgesic index in the research of electroacupuncture. However

the inhibition of behavior resp- onse of pain would be one of the much more effective criteria in a true estimation of acupuncture anaesthesia. The drowsy signs were produced in 13 out of 27 experiments from 6 cats while the microelectrode was inserted into the reticular formation of medulla oblongata. The relationship between drowsy and electroacupunctu- re analgesia

however

is not understood clearly

and needs further studies.