Fig. 5.

Perioperative sciatic nerve block prevents injury-induced changes in rostroventral medulla (RVM) modulation in adulthood. Prior plantar incision was performed at postnatal day (P)3 with perioperative (15 min pre-incision and at 3×2 h intervals) percutaneous sciatic nerve injections of local anesthetic (LA; 40 μl 0.5% levobupivacaine) (P3 incision + sciatic LA, n=5) or saline (P3 incision + saline, n=4). At P40, spinal reflex excitability (quantified as the percentage change from baseline in the area under the mechanical stimulus vs electromyography response relationship) was compared during electrical stimulation of the RVM. Following incision with sciatic block the typical adult response is seen at P40, with facilitation at low intensity (5, 10 and 20 μA) and inhibition at high intensity (50, 100 and 200 μA) RVM stimulation. In the incision with saline group, all intensities of RVM stimulation inhibited reflex excitability. Bars = mean±SEM, *P<0.05, **P<0.01, ***P<0.001 two-way repeated measures ANOVA with treatment as between-subject and stimulus intensity as repeated within-subject variable followed by Bonferrroni post-hoc comparisons.