阿托品、士的宁对电刺激家兔大脑皮层感觉区影响丘脑束旁核神经元伤害性放电的作用

家兔在清醒箭毒化人工呼吸下,采用玻璃微电极细胞外记录束旁核痛抑制单位的放电活动,观察电刺激大脑皮层感觉区对束旁核痛抑制单位伤害性放电的影响,并探讨皮层刺激效应的机理。 23例实验表明,皮层刺激可解除痛抑制单位的伤害性抑制反应,但可为静脉注射阿托品(0.3～0.5mg/kg)或士的宁(0.2mg/kg)所阻断,其中两例痛抑制单位的自发放电,随皮层每一刺激脉冲可出现一阵短暂的遏止,这种遏止反应不为士的宁所阻断。提示:大脑皮层及皮层下中枢的胆碱能系统和甘氨酸可能参与皮层对丘脑束旁核痛抑制单位伤害性抑制反应的下行调节;而在皮层每一刺激遏止一阵痛抑制单位的自发放电活动中,甘氨酸可能不占重要地位。

Effect of Atropine or Strychnine on Nociceptive Discharges of Parafascicular Neurons in Rabbit's Thalamus During Electrical Stimulation of Cortical Sensory Area

The effects of cortical electrical stimulation on nociceptive discharge of parafascicular pain inhibitory unit (PIU) and the mechanism of the cortical stimulatory influence were studied. The study was carried out on conscious curarized rabbits under artificial respiration. 23 PIU showed that the effects of cortical stimulation on the nociceptive inhibitory response of PIU were manifested by disinhibition and these effects could be blocked by atropine (0.3-0.5mg/kg iv) or by strychnine (0.2mg/kg).Among the 23 PIU, two were responded by a brief arrest of PIU spontaneous discharges following each cortical stimulating Pulse and these effects could not be blocked by strychnine. The result indicated that cholinergic systems of cerebral cortex and glycine might participate in the cortical descending influences on the nociceptive inhibitory responses of PIU, whereas glycine might not play an important role during a brief arrest of PIU spontaneous discharges following each cortical stimulating pulse.