CAJ | 학술논문

脊髓背角感觉神经元不仅在感觉信息的传递和调节中起到重要作用,也是各种内源性和外源性药物的作用靶位.为了解静脉麻醉剂异丙酚是否对背角感觉神经元的反应性具有调节作用,本实验采用在体单细胞胞外记录技术,观察了脊髓背表面直接滴注0.5 μmol异丙酚对戊巴比妥钠麻醉大鼠脊髓背角广动力域(WDR)神经元和低阈值机械感受型(LTM)神经元反应性的影响.实验发现,异丙酚能抑制背角WDR神经元由施加于外周感受野伤害性热刺激(45、47、49和53℃,15 s)和夹捏机械刺激(10 s)诱发的反应性,与DMSO对照组比较具有显著性统计学差异(P＜0.05);同样,异丙酚对非伤害性机械刺激诱发的WDR或LTM神经元的反应性也具有显著的抑制作用(P＜0.05).本结果提示,异丙酚可直接作用于正常大鼠脊髓背角神经元,对由非伤害性和伤害性纤维介导的神经元反应性均产生抑制作用,因此异丙酚的脊髓抗伤害作用可能不是特异性的.
척수배각감각신경원불부재감각신식적전체화조절중기도중요작용,야시각충내원성화외원성약물적작용파위.위료해정맥마취제이병분시부대배각감각신경원적반응성구유조절작용,본실험채용재체단세포포외기록기술,관찰료척수배표면직접적주0.5 μmol이병분대무파비타납마취대서척수배각엄동력역(WDR)신경원화저역치궤계감수형(LTM)신경원반응성적영향.실험발현,이병분능억제배각WDR신경원유시가우외주감수야상해성열자격(45、47、49화53℃,15 s)화협날궤계자격(10 s)유발적반응성,여DMSO대조조비교구유현저성통계학차이(P＜0.05);동양,이병분대비상해성궤계자격유발적WDR혹LTM신경원적반응성야구유현저적억제작용(P＜0.05).본결과제시,이병분가직접작용우정상대서척수배각신경원,대유비상해성화상해성섬유개도적신경원반응성균산생억제작용,인차이병분적척수항상해작용가능불시특이성적.
Spinal dorsal horn neurons play an important role in the processing of sensory information and are also targets of modulation by both endogenous and exogenous drugs. Propofol is an intravenous anesthetic and whether it has direct modulatory actions on sensory neuronal responses of the spinal cord dorsal horn has not been well studied. In the present study, a single dose (0.5 ?mol) of propofol dissolved in dimethyl sulfoxide (DMSO) was directly applied onto the dorsal surface of the spinal cord and its effect was evaluated in 25 wide-dynamicrange (WDR) neurons and 10 low-threshold mechanoreceptive (LTM) neurons by using extracellular single unit recording technique in sodium pentobarbital anesthetized rats. Compared with the DMSO treatment, propofol produced a significant inhibition of WDR neuronal activity evoked by both noxious heat (45, 47, 49 or 53℃, 15 s) and mechanical (pinch, 10 s) stimuli applied to their cutaneous receptive fields (cRF)on the ipsilateral hind paw skin. To investigate whether propofol exerts a modulatory effect on non-nociceptive afferent-mediated activity, the responses of WDR or LTM neurons to non-noxious brush and pressure were also evaluated. The non-noxious mechanically-evoked responses of both WDR and LTM neurons were significantly suppressed by propofol. The present results indicate that propofol has direct actions on the dorsal horn neurons of the spinal cord in rats. However, since both non-nociceptive and nociceptive afferent-mediated activity can be suppressed, the spinal effects of propofol are not likely to be specifically associated with anti-nociception.