Fig. 3. Effect of epidural dexmedetomidine on inflammatory hyperalgesia at 15 (  A ) and 30 min (  B ). Within each age group, the change in threshold after inflammation and before epidural injection is standardized as 100% change. The degree of change at subsequent time points is then represented as a proportion of the initial change produced by inflammation (mean ± SEM). At both time points, reversal of inflammatory hyperalgesia is obtained with 1 μg/kg dexmedetomidine in P3 pups, whereas 4 μg/kg is required in P10 and P21 pups. Analysis at these two doses reveals a significantly greater change in P3 pups compared with P21 pups. *  P < 0.05, one-way analysis of variance with Tukey  post hoc comparison; n = 6–8 in all groups.