The aim of the present work is to observe the effects of somatosensory areaⅡ(Sm ) on the descending inhibiting pain activity of nucleus raphe magnus(NRM).The unit discharges in NRM and its responses to noxious stimulationof tail tip were extracellularly recorded with glass microelectrode.The bilateralSm(?) was stimulated by fixed electrodes.Electroacupuncture (EA) of “Zu-sanli” was applied for 5 minutes.Both effects were compared at the same NRMneurons.It was found that stimulation of Sm(?) could activate the excitatoy-neurons in NRM (n=10)

significantly increasing their spontaneous discharges and decreasing their nociceptive responses during 0-20 minutes (P<0.05-0.001).Si-milar results were observed after “Zusanli” EA

increase of their spontaneousdischarges during 0-10 minutes and at 20th minute

and decrease of their nocice-ptive responses during 0-25 minutes were statistically significant (P<0.05-0.001).The results were analysed with the linear regression

it was shown that theeffects of Sm(?) stimulation and “Zusanli” EA on the spontaneous discharges andtheir nociceptive responses of NRM neurons were very similar in level and trend

being the positive correlation (P<0.01-0.001).It is suggested that Sm(?) canactivate the excitatory neurons in NRM

and it is possible that the effect of EAof “Zusanli” on NRM neurons is partially caused by activating Sm (?).