The IP antagonist Cay10441 alleviates zymosan-induced mechanical hyperalgesia. (A) Swiss Webster mice were implanted with an intrathecal catheter and received a zymosan injection (20 µl, 5 mg/ml) in one hind paw. Mechanical pain thresholds were determined at the indicated times. Six hours after zymosan injection, 1 µm Cay10441 (n = 11) or vehicle (n = 8) was administered intrathecally. The intrathecal injection was defined as time point 0 min in the graph. Data are shown as mean ± SEM. Two-way ANOVA with Bonferoni post hoc test, *P < 0.05, **P < 0.01. (B) The levels of the stable prostacyclin-metabolite 6-keto-Prostaglandin F_1α were still increased 6 h after intraplantar zymosan injection (n = 5) compared with levels in control (n = 4). Data are shown as mean ± SEM. Two-tailed Student t test, * P < 0.05.