Fig. 3

OT ameliorated pain sensitization and reduced neuronal activation via OTR. A Timeline for the second experiment. Note that L-368,899 was intraperitoneally injected daily 1 h before OT treatment. The mechanical and thermal pain thresholds of the hind paw and periorbital area were assessed before each NTG injection and on day 11. B, C, D The basal mechanical pain thresholds of the hind paw (B), periorbital area (C), and the thermal pain response of the hind paw (D) were significantly increased in the NTG + OT group compared with the NTG + vehicle group. The pain threshold in the NTG + OT + L368,899 group was markedly decreased compared with the NTG + OT group. Moreover, there was no significant difference between the NTG + vehicle and NTG + OT + L368,899 groups. Two-way ANOVA with the Bonferroni post hoc test, n = 6/group; #p < 0.05, ##p < 0.01, ###p < 0.001 vs. the NTG + vehicle; *p < 0.05, **p < 0.01, ***p < 0.001 vs. the sham group