大脑皮层体感Ⅱ区对中缝大核下行痛抑制活动的调控及其与电针镇痛的关系

用玻璃微电极细胞外记录大鼠(NRM)神经元单位放电及其对尾尖伤害性刺激的反应,研究表明刺激 SmⅡ可增加 NRM 神经元的自发放电,抑制其伤害性反应;与电针对 NRM 的效应相似,发现两者具有相关性。提示:SmⅡ对 NRM 镇痛机制可以发挥下行性调控,电针对 NRM 的影响可能部分是经激活 SmⅡ,再转而作用于 NRM 的。

THE CONTROL OF SOMATOSENSORY AREA Ⅱ ON THE DESCENDING INHIBITING PAIN ACTIVITY OF NUCLEUS RAPHE MAGNUS

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 (?).