ABSTRACT
Aim To study the analgesic effect of geraniol on neuropathic pain and to explore the possible mechanism.Method A neuropathic pain rat model of Spared Nerve Injury(SNI) was established to measure changes in the threshold of paw withdrawal before and after i.p.administration of geraniol.Patch clamp whole-cell recording was performed to measure activity of sodium channels using ipsilateral L3/L4/L5 dorsal root ganglion(DRG) cells isolated from the SNI rats.In addition, HEK 293 cells expressing hNav1.7 and hTRPA1 channels were used for measuring the changes in channel activities with or without geraniol by whole-cell patch clamp.Results Geraniol had a fast analgesic effect on hypersensitivity of mechanical pain in the SNI model.It significantly inhibited sodium channels on DRGs isolated from SNI rats and hNav1.7 but not hTRPA1 channels expressed by HEK293 cells.However, high concentrations of geraniol facilitated the activation of HTRPA1 channel stimulated by AITC.Conclusion Geraniol may abirritate hypersensitivity of mechanical pain in the SNI model by specifically inhibiting Nav1.7 channel activity on the DRG cells.