PIO decreases airway resistance in CRA challenged mice as effectively as DEX. PIO, DEX, or vehicle (Veh) was administered daily (days 14–21). Airway response to challenge with nebulized methacholine was measured in anesthetized mice (8 mice/group) using a plethysmograph specifically designed for whole-body measurements on small animals. Measurements were performed 24 h following final CRA challenge. *P < 0.05 compared to vehicle treatment.