低剂量锰对背根节神经元自发放电的兴奋作用

Excitatory effect of low dose of manganese on spontaneous discharges of dorsal root ganglion neurons

目的探讨低剂量锰对周围神经系统的毒性作用。方法采用离体灌流背根节(DRG)和单纤维记录神经元自发放电的方法,观察不同剂量氯化锰对DRG神经元自发放电的影响。结果不同浓度氯化锰对有自发放电的神经纤维有兴奋作用,随着剂量增加,兴奋作用增强,呈现一定的剂量关系。但氯化锰对静息神经纤维无兴奋作用。不同剂量氯化锰对自发放电频率的兴奋作用呈现不同模式,1μmolLMnCl2作用后,放电频率持续增高。5μmolLMnCl2作用时,放电频率短时间增加后恢复到对照水平,50μmolLMnCl2作用则呈现放电频率先增高后降低的趋势。结论锰对DRG神经元自发放电有兴奋作用,这可能与轻度锰中毒时出现的感觉异常有关。

Objective\ To investigate the toxicity of low dose of manganese on peripheral nervous system. Methods With methods of the perfusion of dorsal root ganglion^DRG) in vitro and single fiber recording of the spontaneous discharges, the effect of manganese chloride ~MnCl_2 1,2,5,10,50,100μmol/L) on neurons were observed. Results MnCl_2 enhanced spontaneous discharges of DRG neurons in dose-dependent manner, but failed to affect the discharges of silent fibers. Different patterns of effects were observed in study. 1μmol/L MnCl_2 persistent enhanced the spontaneous discharges. The frequency of discharges reversed after a transient excitatory effect when 5μmol/L MnCl_2 was applied. However, 50μmol/L MnCl_2 gradually decreased the frequency of discharges followed a transient excitatory effect. Conclusion These results suggest that low dose of manganese enhanced the spontaneous discharges of DRG neurons. This may partially explain the mechanism of paraesthesia in slight poison of manganese.