Alteration of hyperpolarization-activated current ( I _h) 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.