PMA mimic the effect of Sar-SP. A and B:representative traces (A) and histogram (B) showing the effect of PMA on Nav1.8 currents. 300 nM PMA induced a similar potentiation to 1 μM Sar-SP. Perfusion with Sar-SP failed to further enhance the currents after PMA-induced peak potentiation (***p < 0.001, versus control, Kruskal-Wallis one-way ANOVA, n = 16 for control, 10 for PMA and 10 for Sar-SP). PMA also shifted the activation and steady-state inactivation curve of Nav1.8 in a hyperpolarized direction (C and D).