关于痛与镇痛问题的大量研究资料表明

在中枢神经系统中存在着内源性镇痛系统。位于低位脑干的中缝大核在该系统中处于十分重要的地位

它对脊髓水平接受的伤害性输入具有下行性调制作用。但是对该系统上行性作用则了解甚少。丘脑髓板内核群是伤害性信息整合的重要部位。形态学证明中缝核群有广泛的投射到The present work is an investigation of ascending effect of the nucleus raphe magnus and adjacent reticular formation on unit discharges of the nucleus centralis lateralis.Experiments were performed on fifty-nine curarized rabbits under artificial ventilation.The discharges of neurons in the nucleus centralis lateralis were recorded by glass microelectrode.The electrical stimulation(0.2ms

10-20Hz

100-300μA)of the nucleus raphe magnus and adjacent nucleus paragigantocellularis reticularis was given through bipolar concentric electrode.The results showed that;(1)The nociceptive discharges of pain- excitation neurons were modulated either by facilitatory (36/41) or by inhibitory(5/41) effect

after transection of dorsal half of spirral cord

similar effect could be observed:(2)The inhibitory effect on pain-inhibition neurons was released.The results suggest that there may be exist an ascending pain modulating action in thalamus from the nucleus raphe magnus and its adjacent reticular formation.