脊神经结扎慢性痛大鼠背根神经节细胞超极化激活电流(Ih)的变化

目的:研究超极化激活电流( hyperpolarization-activated current, Ih )在慢性神经源性痛中的作用.方法:以单侧L5和L6脊神经结扎制备神经源性痛大鼠模型,运用全细胞电压钳技术记录和分析背根神经节(dorsal root ganglion, DRG)神经元Ih的表达和激活特征.结果:脊神经结扎后,相应节段小直径DRG神经元表达Ih的细胞比率升高,但大、中直径神经元Ih没有改变,另外大、中、小直径神经元Ih的活性增强.结论:神经损伤导致DRG神经元Ih的表达和电流活性发生改变,提示此种电流参与了神经源性痛"外周敏化"的发生.

Alteration of hyperpolarization-activated current (Ih) in dorsal root ganglion neurons in rats with neuropathic pain induced by spinal nerve ligation

SUMMARY Objective:To investigate the roles of hyperpolarization activated current ( I h) of dorsal root ganglion neurons in neuropathic pain. Methods: The neuropathic rat model was prepared by tight ligation of L 5 and L 6 spinal nerves and whole cell voltage clamp technique was applied to examine the changes of I h. Results: After nerve ligation, the incidence of small diameter neurons expressing I h was significantly increased, but the quantities of I h in large and medium diameter neurons remained unchanged. In addition, nerve injury significantly increased I h current activity in all types of DRG neurons. Conclusion: The expression and electrophysiological activity of I h increased in injured DRG neurons, which might serve as one of the mechanisms underlying peripheral sensitivity in chronic neuropathic pain.