Fig. 4

Acute PGE₂-induced sensitization and persistent sensitization after long-term exposure to the eicosanoid are mediated by the same EP receptor subtypes. Each column represents the mean ± SEM of capsaicin-stimulated release of iCGRP as percent of total iCGRP content per well/10 min in cultures maintained in the absence of added NGF and preexposed to vehicle (a) or to 1 μM PGE₂ for 5 days (b). After pretreatment, cultures were acutely exposed to vehicle (lightly shaded columns) or to 1 μM PGE₂ (dark-shaded columns) for 20 min in the absence or presence of EP receptor antagonists, as indicated. An asterisk indicates a statistically significant difference between capsaicin-stimulated release of iCGRP after vehicle versus after PGE₂ using one-way ANOVA followed by Bonferroni’s post hoc test