目的:研究利鲁唑(riluzole)对受损背根节(DRG)A类神经元的不同模式自发放电的作用,并探讨其可能机制。方法:本实验在大鼠L5椎间孔置入不锈钢柱制备大鼠DRG慢性压迫模型(chronic compression of DRG,CCD)上,利用在体单纤维记录的方法观察DRG局部浸浴利鲁唑(500μmol/L)对受损DRG神经元自发放电的影响。结果:(1)CCD大鼠手术后表现出明显的损伤侧机械刺激缩足阈值降低(P〈0.05);(2)利鲁唑对受损DRG神经元自发放电具有明显抑制作用(n=30,P〈0.05);(3)利鲁唑对非周期放电频率的抑制率显著大于对周期放电频率的抑制率(P〈0.05)。结论:利鲁唑对慢性压迫DRGA类神经元的自发放电有显著抑制作用,对非周期放电的抑制作用明显大于对周期放电的作用,呈现出“非周期敏感”的特点,提示受损DRG神经元非周期自发放电行为处于更加不稳定的动力学状态。
Objective: To study the effects of riluzole on the spontaneous discharges of A-type neurons with different firing patterns in the injuried dorsal root ganglion (DRG) and to discuss its possible mechanisms. Methods: We used single fiber recording technique in vivo in the chronic compression of DRG (CCD)model, which was made from inserting a piece of stainless rod into ipsilateral L5 intervertebral foramen in rats. Results: ( 1 ) The thresholds for paw withdrawal on the ipsilateral foot of the C CD animals were clearly reduced after the surgery( P 〈 0. 05 ) ; (2) Riluzole significantly inhibited the spontaneous discharges of compressed A-type DRG neurons ( n = 30, P 〈 0.05 ) ; ( 3 ) The inhibitory effect of riluzole on non-periodic discharges rate was significantly higher than that of riluzole on periodic discharges rate (P 〈 0.05 ). Conclusion: Riluzole obviously inhibits the ectopic spontaneous discharges of compressed A-type DRG neurons. The inhibition of riluzole on compressed A-type DRG neurons with non-periodic firing patterns was more than that of riluzole on A-type DRG neurons with periodic firing patterns ,which is charactered as "sensitivity of non-periodic activity". It suggested that the behavior of spontaneous discharges with non-periodic patterns undergoes more unstable dynamics.