Objective: Pain and hyperalgesia can occur when nerves were injured. The present study aims to examine the electrophysiological changes of dorsal root ganglion (DRG) neurons in rats with neuropathic pain. Methods: The neuropathic pain model in rat was prepared by tight ligation of right side L 5 and L 6 spinal nerve. Whole cell current clamp technique was used for electrophysiological recording. Results: The rheobase and the threshold of action potential were reduced in both small and medium DRG neurons after nerve ligation, while the duration of action potential at half amplitude (APD 0.5 ) was broadened in small injured neurons. Nerve injury also induced spontaneous activities in small neurons. No significant changes were observed in other electrophysiological properties. Conclusion: These results suggested that nerve ligation could induce hyperexcitability of nociceptors, which might be an important mechanism underlying chronic neuropathic pain.
