Fig. 7

P2Y12 receptor in microglia dynamics, neuronal excitability and formalin induced phase-II persistent inflammatory pain. a, b Quantification of microglial motility indices at 40 min after intraplantar injection from WT and P2Y12 knockout (KO) spinal cord slices over a 20 min imaging session (a) or as the group average for each condition (b). Sham, intraplantar saline injection; Formalin, intraplantar formalin injection. Data are shown as mean ± SEM. **P < 0.01, ***P < 0.001, Two-way ANOVA with post hoc comparisons, n = 6–7 slices from 3 to 5 mice per group for slices images. c, d The number of c-fos⁺ cells and pERK⁺ cells were largely reduced in P2Y12 KO mice compared with wild-type mice after formalin injection in the ipsilateral dorsal horn from the WT sham, WT control and P2Y12 KO groups. Data are presented as mean ± SEM; **P < 0.01, ***P < 0.001, compared with WT Control, Two-way ANOVA with post hoc comparisons, n = 5–7 mice/group. e Time course (0–60 min) of formalin-induced spontaneous pain behavior (licking/flinching) in WT control and P2Y12 KO mice, as measured every 5 min. Histogram representing formalin-induced Phase-I (1–10 min) and Phase-II inflammatory pain responses (10–60 min) in WT control and P2Y12 KO mice. Note the formalin-induced Phase-II inflammatory pain is significantly reduced in P2Y12 KO mice. Data are presented as mean ± SEM; *P < 0.05, **P < 0.01, ***P < 0.001, compared to WT control mice, unpaired 2-tailed Student’s t test, n = 8–9 mice/group. f Time course (0–30 min) of bradykinin-induced spontaneous pain behavior (licking/flinching) in WT control and P2Y12 KO mice, as measured every 5 min. Histogram representing bradykinin-induced inflammatory pain responses within 0–5 min, 5–30 min and 0–30 min in WT control and P2Y12 KO mice. Bradykinin-induced inflammatory pain is reduced within 5–30 min and 0–30 min in P2Y12 KO mice. Data are presented as mean ± SEM; *P < 0.05, compared to WT control mice, Two-way ANOVA with post hoc comparisons, n = 5–8 mice/group