Fig. 7. ( A ) Current traces of control sodium currents (INa) in right pedal dorsal 1 neuron. Thirteen steps to potentials between −80 and +40 mV for 20 ms. ( B ) Current traces of INa after lidocaine (1 mm) perfusion. ( C ) Closed circles =current–voltage curves of INa in the control (n =7); open triangles =0.1 mm lidocaine perfusion (n =7); open squares =1 mm lidocaine perfusion (n =7). Results are presented as mean ± SEM. The black arrow shows the INa at resting membrane potential (−60 mV) in the control. The horizontal gray arrow shows the direction of membrane potential change from the resting level (−60 mV) to the potential after lidocaine (1 mm) perfusion. The vertical gray arrow highlights the inward sodium current generated by stepping the membrane potential to this depolarized potential of −20 mV, in patch clamp configuration.