目的 通过观察背根神经节细胞的动作电位特征在糖尿病大鼠周围神经病变中的变化,以探讨糖尿病大鼠周围神经病变引起痛觉过敏的发生机制.方法 运用全细胞电流钳技术对糖尿病周围神经痛觉过敏大鼠背根神经节细胞进行电生理记录,与正常大鼠比较静息电位水平、动作电位峰值、动作电时程变化、基强度、动作电位爆发阈值.结果 与正常组比较,糖尿病神经痛大鼠背根神经节细胞静息电位水平和动作电位峰值无显著差异;大、中、小直径神经元动作电位与正常大鼠比较爆发阈值下降,动作电时程变宽,基强度显著降低.结论 糖尿病大鼠周围神经病变引起初级感觉神经元背根神经节细胞的兴奋性增强,这可能是引起糖尿病大鼠周围神经痛觉过敏原因之一.%Objective To explore the mechanism of hyperalgesia during diabetic peripheral neuropathy by examining the cellular electrophysiological changes of dorsal root ganglion neurons in rats with painful diabetic peripheral neuropathy. Methods Dorsal root ganglion neurons from rats with painful diabetic peripheral neuropathy ( DPN group ) and counterparts from normal rats ( control group ) were selected for electrophysiologically recording the whole cell current. The resting potential ( Vrest ) , action potential peak amplitude ( Vpeak ) , action potential duration at half amplitude( APD0.5 ) , theobase, action potential threshold( Vthreshold ) were recorded and compared hetween 2 groups. Results Vrest and Vpeak showed no significant difference between two groups. The threshold of action potential outbreak was reduced and the duration of action potential was broadened in large,medium and small dorsal root ganglion neurons from rats with diabetic peripheral neuropathy. The lower theobase was observed in large,medium and small dorsal root ganglion neurons from rats with diabetic peripheral neuropathy. Conclusion These results suggest that painful diabetic peripheral neuropathy could induce hyperexcitability of primary sensory neurons.which might be an important mechanism for hyperalgesia during diabetic peripheral neuropathy.
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