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

耳聋疼痛患者的脊髓背角和丘脑中存在高频放电神经元。我们密切关注高频放电神经元（超活跃神经元）与失聪性疼痛的关系。在人体中，在植入深度刺激电极之前，通过微电极记录细胞外单位活动。Vc核可见大量过度活跃的神经元。间隔直方图有三种放电模式。因此，静脉注射苯妥英和尼卡地平后，过度活跃的神经元在短时间内表现出放电抑制。在动物实验中，根据Lombard et al .（1979）的方法，对雄性Wistarr犬进行C5至Th1的单侧背根切除。术后几个月，丘脑核和内侧小网膜出现了异常活跃的神经元。过度活跃神经元的放电模式和分布与人类非常相似。这些高度活跃的神经元不受电刺激的影响，它们的核被电刺激，而核被电刺激的区域则被电刺激的区域被电刺激。苯二氮卓和倒刺的阳离子显示放电减少。谷氨酸盐的垂直施用使其呈增焦状。相比之下，GABA和NMDA拮抗剂MK- 801表现出明显的放电抑制作用。这些结果提示，神经元的过度活跃可能与谷氨酸能，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.