Effects of gabapentin on high voltage active calcium currents in injured dorsal root ganglion neurons in a rat model of neuropathic pain

Objective To investigate the effect of gabapentin on high voltage active calcium currents in the injured dorsal root ganglion (DRG) neurons in a rat model of neuropathic pain.Methods Pathogen-free male SD rats aged 4-6 weeks were used in this study. The animals were anesthetized with intraperitoneal pentobarbital soclium 50 mg/kg. L_5 spinal nerve was ligated between DRG and sciatic nerve and cut distal to the ligature. The animals were decapitated on the 14th postoperative day. L_5 DRG was isolated and the neurons in the ganglion were enzymatically dissociated. The high voltage active calcium current was recorded using whole-cell patch-clamp technique.Results Gabapentin inhibited the peak calcium current in the injured DEG neurons. Peak calcium current was decreased by gabapentin 100 μmol/L and both activation and steady-state inactivation curve shifted to more hyperpolarized potentials. Conclusion Gabapentin can inhibit high voltage active in the injured DRG neurons in a rat model of neuropathic pain. The alteration in the inactivation of the electrophysiological properties may be involved in the mechanism. Key words: Cyclohexanecarboxylic acids; Calcium channels; Neuralgia; Ganglia, spinal; Neurons