中文摘要：

目的：研究甲钴胺（methylcobalamin,Methyl B12）对损伤背根节（dorsal root ganglion,DRG）A-类神经元的不同模式自发放电的作用。方法：在大鼠L5椎间孔植入不锈钢柱制备大鼠DRG慢性压迫模型（chronic com-pression of DRG,CCD）上,利用在体单纤维细胞外记录方法研究Methyl B12对受损DRG神经元自发放电的影响。结果：（1）CCD模型大鼠出现明显的双侧机械刺激引起缩足反应阈值降低（P〈0.001）;（2）Methyl B12（300μmol/L）对受损A-类DRG神经元自发放电具有显著的抑制作用（n=13,P〈0.05）;（3）Methyl B12（300μmol/L）对受损A-类DRG神经元非周期和周期放电模式自发放电均有抑制作用,且两者之间没有明显差异。结论：Methyl B12（300μmol/L）对受损DRG A-类神经元产生的异位自发放电具有抑制作用,且对于非周期和周期放电模式的抑制作用没有差异。

英文摘要：

Objective： To explore the effects of methylcobalamin （Methyl B12） on the spontaneous discharges of A-type neuron with different firing patterns in the injured dorsal root ganglion （DRG） . Methods： The extracellular single fiber recording technique in vivo was applied on the chronic compression of DRG （CCD） models which was made by inserting a piece of stainless rod into the ipsilateral L5 intervertebral foramen of rats and recorded the the effects of Methyl B12 on the spontaneous discharges of the injured DRG neurons. Results ： （ 1 ） The bilateral mechanical paw withdrawal thresholds were significantly decreased after CCD in the experimental and control group （ P 〈 0. 001 ） ; （ 2 ） Spontaneous discharges of A-type DRG neurons were obviously inhibited by Methyl B12 （300 μmol/L, n = 13, P 〈 0.05） ; （3） The discharge frequency of non-periodic and periodic discharge pattern were both depressed by Methyl B12 （300 μmol/L） , but there was no significant difference between them. Conclusion： The spontaneous discharges of chronic compressed DRG A-type neurons were greatly inhibited by Methyl B12 （300 μmol/L）. And there was no significant difference of inhibition induced by Methyl B12 between non-periodic and periodic discharge patterns.