Fig. 5.

Effect of co-application of capsaicin and QX-314 on I_Na and APs in nociceptive dental primary afferent neurons. (A) (a) Upper panel: a representative recordings following the application or co-application of QX-314 (5 mM) and capsaicin (1 µM, 1 min) in dental primary afferent neurons. Lower panel: superimposed I_Na evoked by test pulse at the points indicated at the upper panel. (b) Collected results for the effects of QX-314, capsaicin, or co-application of both compounds on I_Na in nociceptive dental primary afferent TG neurons. (c) Dental primary afferent neurons were identified by retrograde labeling with a fluorescent dye, DiI, placed into the molar teeth. The photograph of TG neurons shows TRPV1-immunoreactivity (green), DiI (red), DAPI (blue) and merged. Scale bar = 50 µm. (B) (a) Upper panel: a representative recording following the application or co-application of QX-314 (5 mM) and capsaicin (1 µM, 5 min). Lower panel: APs recorded at the time points indicated at the upper panel. (b) Summary of the effects of QX-314, capsaicin, or co-application of both on AP amplitude in nociceptive dental primary afferent neurons. TG neurons were small sized (<25 µm in diameter) with the resting membrane potential (V_res) of −55.6 ± 3.2 mV. The numbers in parentheses indicate the number of cells tested. Results are means ± S.E.M. *P < 0.05 compared with the control (the AP amplitude before drug application).