Mechanisms of deafferentation pain : examination in human and animal central nervous systems

在脊髓背角和丘脑内发现高频放电神经元.我们密切关注与去交感神经痛有关的高频放电神经元（高活动神经元），在人体，在植入深度刺激电极之前，用微电极记录细胞外单位活动。从Vc核中记录到大量的过度活跃的神经元。在间期直方图上有三种类型的放电模式。在麻醉实验中，按Lombard等（1979）的方法切除雄性Wistar大鼠一侧C_5 ~ Th_1背根。手术后几个月，从丘脑核和内侧丘系记录到过度活跃的神经元。多动神经元的放电模式和分布与人类非常相似。这些神经元不受电刺激的母鸡的核或盐和I ocus ceruleus。苯二氮卓类药物和巴比妥类药物的治疗显示放电减少，谷氨酸盐的电渗透治疗显示放电增加。而GABA和NMDA拮抗剂MK- 801则表现出明显的放电抑制作用。这些结果提示，兴奋神经元可能与多巴胺能，特别是NMDA和GABA能受体或纤维有关。

Neurones with high- frequency dischargew ere found in the spinal dorsal horn and the thalamus of deaffer entation pain patients. We paid close attention to the high- frequency discharging neurones (hyper active neurones) in relation to deaffere ntation pain.In human, prior to implantation of the deeps timulating electrodes, extracellular unitary activity was recorded by microelectrodes. A significant number of hyperactive neurones were recorded from the Vc nucleus. There were three types of discharge patterns in interval histograms. So me hyperactive neurones showed firing suppuression for a short time peri odb y intravenous administration of p henytoin a ndC alciuma ntagonist (Nicardipine).In a nimal experiments, unilateral dorsal roots ectioning from C5 to Th1 were made in male Wistarr ats according to the method of Lombard et al(1979). A few months after the operation, hyperactive neurones were recorded from the thalamic nuclei and lemniscus medialis. The firing patterns and distri bution of hyperactive neurones were very similar to those of humans. These hyper active neurones were unaffected by electrical stimulation of t hen ucleus r aphe d or salis and I ocus c eruleus. A ppi cation of benzodiazepine an d barb it ur ate showed reduction of firing.lontophoretical application of glutamate showed an in crease in firing. In contrast, GABA and NMDA antagonist MK- 801 showed remarkable firing suppression. These results suggest that hyperactive neurone may correlate with the glutamatergic, especially NMDA and GABA ergic receptor or fibers.