Basic research on pathophysiology of nerve root

本研究旨在从异位放电的角度探讨机械刺激、化学刺激和髓核应用后背根神经节（DRG）的功能变化。使用成年Wister大鼠。在脊神经切断的情况下，从腓肠神经记录DRG的异位放电。分析髓核对背根节的影响：将自体髓核植入背根节，观察1、2、4周后的异位放电。在髓核治疗后1至4周观察到高异位放电。机械压迫和化学介质的影响：用硅胶管压迫马尾神经，异位放电较对照组明显增加。将一氧化氮释放剂硝普钠（sodium-nitroprussid）作用于DRG，压迫尾节的动物的异位放电增加明显高于对照组，说明机械压迫、一氧化氮等化学介质和髓核诱导的次级介质参与了异位放电。这些现象可能与腰椎间盘突出症的主要症状之一坐骨神经痛的产生有关。

The purpose of this study is to investigate the functional changes of dorsal root ganglia (DRG) from a view point of ectopic firing after mechanical stimulation, chemical stimulation and application of nucleus pulposus. Adult Wister rats were used. The ectopic firing from DRG was recorded from sural nerve under spinalization.I. Analysis of the effect of nucleus pulposus on DRG.The autologous nucleus pulposus was applied to DRG and ectopic firing was observed at 1, 2 and 4 weeks later. High ectopic firing was observed after 1 to 4 weeks after the nucleus pulposus treatment.II. Effects of mechanical compression and chemical mediator.The compression of cauda equine was made by silicon tube, then ectopic firing was significantly increased comparing to control animal. When sodium-nitroprussid, which is nitric oxide releaser, was applied to DRG, the animal with cauda compression showed much higher increase of ectopic firing than control animal.These results demonstrated that mechanical compression, chemical mediator such as nitric oxide and secondary mediators induced by nucleus pulposus contribute to ectopic firing. These phenomena may be related to production of sciatica which is a main symptom of lumbar disc herniation.