受损背根节A类神经元的阈下膜电位振荡

SUBTHRESHOLD MEMBRANE POTENTIAL OSCILLATION IN INJURED A-TYPE DRG NEURONS

摘要:

目的：研究慢性压迫大鼠背根神经节(dorsal root ganglion，DRG)神经元阈下膜电位振荡(subthreshold membrane potential oscillation，SMPO)的特征及其与异位自发放电的关系。方法：采用在体DRG神经元细胞内记录。结果：在慢性压迫的650例DRG神经元，93例A类神经元出现具有特定频率及幅值的SMPO。对其进行研究发现，异位自发放电起始于SMPO的上升相，SMPO的规则、梭形及不规则形式分别决定了异位自发放电的周期／整数倍、阵发及不规则放电模式。有SMPO的神经元，其兴奋性高于没有SMPO的神经元。此外，低浓度河豚毒可以阻断SMPO的产生，进而消除异位自发放电。结论：阈下膜电位振荡是产生异位自发放电的基础，反映了初级感觉神经元超兴奋的基本电生理变化。

Abstract:

Objective: To study the characteristics of subthreshold membrane potential oscillation (SMPO) and its relation with ectopic spontaneous discharge on chronic compressed dorsal root ganglion (DRG)neurons. Methods: Intracellular recording in vivo on DRG neurons was used for electrophysiological recording. Results: Out of 650 neurons, 93 A-type neurons displayed SMPOs. Regular pattern, spindle-like pattern and irregular pattern of SMPO had been observed. Further observation showed that the spontaneous discharge of injured neurons usually occurred on the depolarizing phase of oscillations. In addition, the regular pattern of SMPO was grounded on the period and integer multiple patterns of spontaneous discharges. The spindle-like pattern of SMPO contributed to bursting spontaneous discharge. The irregular pattern of SMPO had a striking relation with irregular spontaneous discharge. Compared with normal DRG neurons or injured but without SMPO ones, the injured DRG neurons with SMPO had the lowest spike threshold in accordance with the detection of spike accommodation. Conclusion: Results show that neurons with SMPO in injured DRG have a higher excitability than that without SMPO and that the SMPO underlie the occurrence of ectopic spontaneous discharges, which suggest that SMPO is the basic electrophysiological changes of hyperexcitability neurons.