Fig. 1

Acute glyceryl trinitrate (GTN) administration produces transient allodynia and photophobia. A The schematic illustration of the von Frey test indicates the region where the von Frey stimulus was applied during testing. B and C Time course of GTN-induced changes in left hind paw (B) and head withdrawal thresholds (C) based on von Frey tests. D and G Example traces of mice in 20-min light-aversive test at 1 h (D) and 2 h (G) after VEH or GTN injection. E and H Average time spent in light for each group per 5-min interval (left panel) and over a total of 20 min (right panel) at 1 h (E) and 2 h (H) after VEH or GTN injection. F and I The number of transitions between zones expressed as the average for each group per 5-min interval (left panel) and during a total of 20 min (right panel) at 1 h (F) and 2 h (I) after VEH or GTN injection. n = 9 mice per group. Significance was assessed by two-way repeated-measures ANOVA with post hoc comparison between groups (B, C, E left panel, F left panel, H left panel, and I left panel) or by two-tailed unpaired Student’s t-test (E right panel, F right panel, H right panel, and I right panel). All data are presented as the mean ± S.E.M. *P < 0.05, **P < 0.01, ***P < 0.001