Effects of topical application of naproxen on sensitized meningeal nociceptors. Mean ± SEM response magnitude to mechanical stimulation of the dura using threshold (A) and suprathreshold (B) pressure stimuli, and ongoing firing rate (C) before (white) and after IS (black), and again after treatment (grey). Friedman test: comparing all six time points (α = 0.05): P ≤ 0.001 (A and B), P ≤ 0.05 (C); comparing five time points from 0 to 60 min (α = 0.025): P ≤ 0.001 (A and B), P = 0.031 (C). BL, baseline.