Fig. 3.

1-O-acetylgeopyxin A inhibits total Na⁺ currents in dorsal root ganglion (DRG) neurons. a Activation protocol: Currents were evoked by 150 ms pulse between − 70 and + 60 mV (+ 5 mV steps) (left). Inactivation protocol: Cells were subjected to hyperpolarizing/ repolarizing pulses for 1 s between − 120 and 10 mV (+ 10 mV steps), followed by a 0-mV test pulse for 200 ms (right). b Representative traces of Na⁺ currents from DRG sensory neurons treated with 0.1% DMSO (control) or 20 μM 1-O-acetylgeopyxin A. c, d Summary (± SEM) of the normalized (pA/pF) sodium current density versus voltage relationship (c) and peak Na⁺ current density at − 10 mV (mean ± SEM) (d) from DRG neurons treated as indicated. e, f Boltzmann fits for normalized conductance, G/Gmax, voltage relations for voltage dependent activation (e) and inactivation (f) of sensory neurons treated as indicated. V_1/2 values for activation and inactivation are presented in Table 1. Asterisk indicate statistical significance compared with cells treated with 0.1% DMSO (*P < 0.05, unpaired two-tailed Student’s t test, n = 16–19 per condition)