Fig. 4

Activation of PACAP38-MrgprB2 pathway sensitizes TG neurons. a Representative images of in vivo TG neurons activated by 0.4 g von Frey filament application onto V1 region in PACAP38-injected mice. V1 (ophthalmic), V2 (maxillary), and V3 (mandibular) indicate the location of neuron cell bodies in TG imaging. White arrowheads indicate activated neurons. b and c Number of individual TG neurons activated by (b) 0.4 g von Frey filament or (c) capsaicin in stressed mice (n = 6 WT CON, 6 WT STR, and 5 KO STR). d and e Number of individual TG neurons activated by (d) 0.4 g von Frey filament or (e) capsaicin in PACAP38-injected mice (n = 6 mice per group). Small-diameter TG neurons (< 20 μm); medium (20–25 μm); large (> 25 μm). CON: control, KO: knock-out, STR: stress, Veh: vehicle, WT: wild-type. Error bars indicate S.E.M. *p < 0.05; **p < 0.01; ***p < 0.001; (b-e) one-way ANOVA with Tukey’s multiple comparison post-hoc test