关于大脑皮层参与疼痛及针刺镇痛过程的研究

近年来国内已有报导。我们也观察到电刺激大脑皮层体感Ⅱ区(SⅡ)

可减弱丘脑中央中核(CM)神经元的伤害性反应

电针穴位同样获得CM神经元伤害性反应的抑制效应。我们设想大脑皮层参与疼痛及镇痛过程的机制可能是通过各种信息在皮层内的整合

也可能是通过某些信息影响皮层后产生了下行性作用。虽然

起源于皮层的下行冲动可影响皮层下许多神经元的活动

但对于伤害性传入信息的下行性影响较少研究

尤其是来自大脑皮层体感Ⅱ区Based upon the previous study we suggest that there are two routes by which the cerebral cortex modulate pain and acupuncture analgesia. One ro- ute is the cerebral convergence and the other is the corticofugal influence. Some subcortical neurons recieve corticofugal influence. But it is unkown whether it plays a part in modulation nocieptive afferents. The aim of this paper is to investigate the corticofugal modulation on nucleus parafascicu- laris after electroacuptuncture by topical administration of GABA on SII. Experiments were carried out on awake and restrained cats. Electrial sti- mulation of the n. suralis was used as the noxious stimulation. Single unit activites were record with glass microelectrodes extracellularly. The range of the Pf neurons recorded was A 6.5--7.0

L 0.5--1.0

H 0--3. "Zusanli" and "Huan tiao"

points were stimulated by the electro-acupuncture unilateraly with intensity of 2.2V and frequency of 100Hz. GABA was applied topi- cally by means of 3x2mm

2

filter paper and placed on the SII. All Pf neu- rons were checked histologically. It was shown that the responses of most units evoked by noxious sti- mulation were inhibited after electroacuptuncture. On the contrary

the acu- puncture effect on Pf neurons was abolished when GABA was administed on SII. However

the effect of saline control resembled that of simple acu- punctre. By comparison between GABA and saline or GABA and simple acupuncture in the same neurons respectively the results were the same as that in comparison between two groups. This result suggested that the co- rticofugal modulation from SII may play a role in acupuncture analgesia.