甲钴胺对大鼠受损背根节A-类神经元自发放电的抑制作用

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。

Inhibitory effects of methylcobalamin on the spontaneous discharges of chronically compressed A-type dorsal root ganglion neurons of rats

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.