Figure 4.

Airway responsiveness to methacholine in PGHS-deficient and wild-type mice. Wild-type, PGHS-1^–/–, and PGHS-2^–/– mice were divided into treatment groups as described in Figure 1. Airway responses to intravenous Mch were measured 1 day after final aerosol exposure, as described in Methods. Bars represent mean ± SE of 7–13 mice per group. (a) R_T before dosing with Mch and at peak of response to 25, 50, 100, and 200 μg/kg Mch (left to right for each group). For each dose, significant differences among groups were determined for associated baselines (shown above hatched bars) and increases in R_T due to Mch (shown above open bars). *P < 0.05 vs. all other groups. ^†P < 0.05 vs. wild-type saline. ^§P < 0.05 vs. all groups except wild-type OVA. (b) Total respiratory system-compliance (C_T), measured simultaneously with R_T, before dosing with Mch and at nadir of response to Mch. For each dose, significant differences among groups were determined for associated baselines (hatched bars + open bars; shown above open bars) and decreases in C_T due to Mch (shown within open bars). *P < 0.05 vs. wild-type saline, wild-type OVA, PGHS-1^–/– saline, and PGHS-2^–/– saline. ^†P < 0.05 vs. PGHS-1^–/– saline and PGHS-2^–/– OVA. ^§P < 0.05 vs. wild-type OVA and PGHS-1^–/– saline. ^‡P < 0.05 vs. PGHS-2^–/– saline.