Abstract: The effects of hydrogen sulfide(H₂S)on tetrodotoxin-sensitive(TTX-S)sodium currents in mouse dorsal root ganglion(DRG)neurons, were studied by use of the whole-cell patch clamp technique. NaHS(a donor of H₂S)increased TTX-S sodium currents in a concentration-dependent manner; the EC₅₀ was 119 μmol/L and Hill coefficient was 1. 105. NaHS 100 μmol/L markedly shifted the steady state activation and inactivation curves of TTX-S sodium currents towards more positive potential to 9. 8 and 10. 4 mV, respectively, yet with no significant difference on recovery from inactivation of TTX-S sodium channels. Therefore, H₂S increased the TTX-S sodium currents and altered the activation and the inactivation kinetics of TTX-S sodium channel, which may contribute to one of its mechanisms in pain.