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. Author manuscript; available in PMC: 2021 Apr 1.
Published in final edited form as: Neuropeptides. 2020 Jan 24;80:102024. doi: 10.1016/j.npep.2020.102024

Figure 3. Nerve injury-induced latent pain sensitization requires spinal NMDAR.

Figure 3.

A–B) Time course of mechanical (A) and cold (B) thresholds at pre-surgery baseline, d3, d28 after CpxSx surgery, and 30 and 60 min after the 2nd i.t. injection. A–B, Left) Progression and resolution of CpxSx-induced mechanical and cold hypersensitivity. Pre-injection: n=5 (sham); n=29 (CpxSx). ★P < 0.05 (CpxSx vs sham). A–B, Right) 28 days after CpxSx surgery, MK801 (MK, 1 μg/5 μl) or vehicle (Veh) was followed 15 min later with injection of BIBO3304 (BIBO, 5 μg/5 μl) or vehicle. Post-injection n=5 (CpxSx, Veh+Veh); n=5 (CpxSx, MK801+Veh); n=10 (CpxSx, Veh+BIBO); n=8 (CpxSx, MK801+Veh); n=5 (sham, Veh+Veh). MK-801 prevented BIBO3304-evoked reinstatement of mechanical and cold hypersensitivity. ★P < 0.05 (MK801 + BIBO vs Veh + BIBO), #P < 0.05 (Veh + BIBO vs Veh + Veh). C) time spent in side chambers during the preconditioning and postconditioning test phases of a CPA assay conducted 28 days after CpxSx surgery. D) difference score of postconditioning minus preconditioning values. MK801 prevented BIBO3304-evoked affective pain [difference scores as postconditioning minus preconditioning values; n=10 per group, ★P < 0.05 (BIBO+Veh: vehicle vs drug chamber)]. vs drug chamber. CPA and CPP: #P < 0.05, Pre vs Post; ★P < 0.05 vehicle vs drug chamber. Some data in A and B are the same as shown in Fig 2A and 2B, respectively. Values represent mean ± SEM.