Fig. 4

Pretreatment with an α7 nAChRs selective antagonist prevents 4R-induced reductions in inflammation-induced hypersensitivity and paw edema (a) Experimental timeline. CFA-injected and non-injected paw thickness measurements were taken in pre-drug condition. One day after CFA paw injection, MLA (10 mg/kg) or vehicle (veh) was systemically administered and 15 min after, animals received 4R (15 mg/kg) or veh treatment (s.c.). CFA-injected and non-injected paw thickness was measured 1–8 days after 4R (15 mg/kg), MLA (10 mg/kg) or vehicle administration. Acetone (cold) and Hargreaves (heat) tests in CFA-injected and non-injected hind paws were performed 7–8 days after systemic drug administration. (b, c) Acetone response scores (b) and paw withdrawal latencies in response to heat stimulation (c); Kruskal–Wallis test followed by posthoc Dunn’s multiple comparison test; saline + 4R vs. MLA + 4R; p < 0.01 (##); saline + DMSO vs. MLA + DMSO, p > 0.05, not significant (ns). (d) Thickness measurements of CFA-injected and non-injected hind paws; Two-way RM ANOVA followed by posthoc Tukey’s multiple comparisons test: CFA-injected paw vs uninjected paw in pre-drug veh conditions, p < 0.0001 (####). Two-way RM ANOVA followed by posthoc Tukey’s multiple comparisons test: CFA-injected paws in saline + DMSO vs saline + 4R systemic treatments and MLA + 4R vs saline + 4R at the same time-point, p < 0.05 (*), p < 0.01 (**). All values are expressed as mean ± SEM. n = 6 animals per treatment and test