Latent sensitization in pENK, pOMC, and pDYN KO mice. Mice were injected in the hindpaw with 5 μl of CFA and, upon return to baseline, they received NTX (3 mg/kg, s.c.). PWTs to von Frey filaments were obtained on the days indicated. A, pENK KO mice (n = 10) and their WT littermates (n = 5). B, NTX injected on day 28 to pENK KO and WT mice reinstated hyperalgesia. C, pOMC KO mice (n = 5) and their WT littermates (n = 4). D, NTX injected on day 56 to pOMC KO and WT mice reinstated hyperalgesia. E, pDYN KO mice (n = 8) and their WT littermates (n = 8). F, NTX injected on day 35 to pDYN KO and WT mice reinstated hyperalgesia. G, JDTic (10 mg/kg, s.c.) injected on day 58 to pDYN KO and WT mice reinstated hyperalgesia after 1 d. Holm-Sidak's post hoc tests of two-way ANOVA: *p < 0.05, **p < 0.01, ***p < 0.001 compared with baseline (time 0 d or 0 min).