Objective: To explore the modulatory effect of niflumic acid (NFA) on gamma aminobutyric acid (GABA)-activated currents of dorsal root ganglion (DRG) neurons in rat.
Methods: The whole-cell patch-clamp technique was used to record the NFA- and GABA-activated currents in neurons freshly dissociated from rat DRG neurons.
Results: Application of NFA(0.1 - 100 micromol/L) could induce concentration-dependent outward currents in some cells (21/48,43.75%), and GABA (0.1 - 100 micromol/L) could induce concentration-dependent inward currents in some cells(150/159,94.32%). NFA-(100 micromol/L) and GABA-(100 micromol/L) activated currents were (0.27 +/- 0.06) nA (n = 12) and (1.29 +/- 0.72) nA (n = 53) respectively. However, pre-application of NFA (0.1 - 100 micromol/L) could inhibit the GABA-activated inward current which was identified to be GABAA receptor-mediated current. The inhibitory effects of NFA were concentration-dependent. NFA could not alter the EC50 (about 30 micromol/L) and inverse potential (about -10 mV) of GABA-activated current (P > 0.05).
Conclusion: Pre-application of NFA exerts a more strong inhibitory effect on the peak value of GABA-activated current.