目的　了解C纤维支配的感受单位 (C单位 )在糖尿病性神经病患者产生疼痛和感觉异常中的作用。　　方法　用神经内微记录 (INMR)方法 ,观察糖尿病性神经病患者桡神经浅支中C单位的反应特性。　　结果　糖尿病组的部分C单位具有自发放电 ,所有C单位的机械阈值明显降低 ,传导速度 (CV)显著减慢。它们对持续 1分钟的机械性阈刺激的反应同对照组相似 ,而在阈上机械性刺激期间放电频率明显增加 ,撤除阈刺激和阈上刺激后 ,后放电显著增多。在糖尿病组的C单位中三种亚单位的比例同对照组没有显著差异。　　结论　提示糖尿病组C单位的异常放电活动是患者产生疼痛和感觉异常的外周因素 Objective To understand the role of C-fiber-dominated units of perception (C-units) in the development of pain and sensory abnormalities in patients with diabetic neuropathy. Methods The intracranial microinjection (INMR) method was used to observe the response characteristics of C unit in the superficial branch of radial nerve in patients with diabetic neuropathy. Results Some C units in diabetic group had spontaneous discharge, and the mechanical threshold of all C units was significantly decreased and the conduction velocity (CV) was significantly slowed down. Their response to mechanical threshold stimulation for 1 minute was similar to that of the control group, while the discharge frequency was significantly increased during the suprathreshold mechanical stimulation and was significantly increased after removal of the threshold and suprathreshold stimuli. There was no significant difference in the proportions of the three subunits in the C unit of the diabetic group from the control group. Conclusions suggest that abnormal discharge activity of C unit in diabetic group is a peripheral factor causing pain and abnormality in patients