Effects of QX-314 and capsaicin on action potentials in capsaicin-sensitive TG neurons. Representative current-clamp recordings over time following the application of QX-314 (5 mM, 5 min) (A), capsaicin (1 µM, 5 min) (B) or co-application of capsaicin and QX-314 (5 min) (C). Upper panel: action potentials (APs) were elicited by injection of 3-ms depolarizing current pulses with 250 pA amplitude. Note that membrane depolarization and transient action potential discharges were evoked by capsaicin in the capsaicin-sensitive TG neurons. Lower panel: APs recorded at the time points indicated at each upper panel. Arrow indicates the typical hump in the falling phase of AP in the capsaicin-sensitive TG neurons. (D) Collected results for the effects of QX-314, capsaicin, or co-application of both on AP amplitude in capsaicin-sensitive TG neurons. The numbers in parentheses indicate the number of cells tested. Results are means ± S.E.M. *P < 0.05 compared with the control (AP amplitude before drug application).