Measurement of Airway Hyperresponsiveness

Mice were anesthetized and airway resistance to different doses of methacholine was measured using an Elan RC Fine Pointe system (Buxco, Wilmington, NC), as previously described²⁴. Mice were mechanically ventilated following tracheal cannulation with a 19-gauge beveled metal catheter, with a constant inspiratory flow before nebulization with increasing doses of methacholine (0-10 mg/ml). Airway resistance was recorded at 10-seconds interval for 3 mins and average values are represented as cm-H₂O/ml/s.