Assessment of AHR to Mch
AHR was assessed using a whole-body plethysmography system (Enterprise EMKA Technologies, Paris, France), as described elsewhere[19]. Unrestrained, spontaneously breathing mice were placed into chambers. The enhanced pause (Penh), a function of the maximal expiratory and inspiratory box pressure signals and the timing of expiration that is closely related to pulmonary resistance, was calculated. Mice were exposed for 2 min to nebulized PBS, then to increasing concentrations (3.125, 6.25, 12.5, 25, and 50 mg/mL) of nebulized Mch in PBS. After each nebulization, 3 min recordings were taken. Penh measurements were averaged for each Mch concentration.