低频电疗对周围神经损伤后白鼠的脊髓后角神经细胞活动电位的影响

Effects of transcutaneous nerve stimulation on dorsal horn cell activity in neuropathic rats

目的:应用周围神经损伤的动物模型,探讨低频电疗对被机械性刺激和温度刺激所引发的脊髓后角神经细胞活动电位(膜电位)的影响。方法:用Sprague-Dawley雄性白鼠,制作出周围神经损伤疼痛模型作为实验组。用行动学和电生理学方法测定后腿的躲避反应和脊髓后角神经细胞的膜电位,并与对照组进行比较。结果:①实验组被机械性刺激和温度刺激所引发的躲避反应频率明显高于对照组(P<0.01)。②实验组被机械性刺激和温度刺激所引发的脊髓后角神经细胞膜电位明显高于对照组(P<0.01)。③实验组经低频电刺激10min后,其脊髓后角神经细胞的膜电位明显低于低频电刺激前脊髓后角神经细胞的膜电位(P<0.01)。④在实验组低频电刺激的同时静脉注射纳络酮10min后,其脊髓后角神经细胞的膜电位明显高于未注射纳络酮组(P<0.01)。结论:低频电缓解周围神经损伤所致疼痛的作用机理可能与其促进分泌内啡呔等中枢鸦片样物质,作用于脊髓后角神经细胞,降低其活性有关。

Objective:To study the effects of transcutaneous electrical nerve stimulation(TENS)on the non-invasive evoked dorsal horn cell activities applied to the somatic receptive field in neuropathic pain model.Method:Sprague-Dawley(250-300g)rats were used to made neuropathic pain model.After neuropathic pain was developed,pain sensitivity and extracellular action potentials were assessed through behavioral and electrophysiological test.Result:①Pain sensitivity assessed through behavioral test in experimental group was higher than that of control group(P<0.01).②Cell activities produced by both mechanical and thermal stimulation in the neuropathic rats were significantly higher than those in the control rats(P<0.01).③After TENS,the non-invasive evoked activities of the dorsal horn cells were significantly decreased in the neuropathic rats(P<0.01).④Depressive effects of TENS on the activities of the dorsal horn cell activities of the dorsal horn cells were reversed by the intravenous administration of naloxone(P<0.01).Conclusion:Spinal dorsal horn cells are involved in the effects of TENS on reducing allody-nia.Low-frequency TENS can modulate the activity of dorsal horn cell and that by activating endogenous opioids system.