Figure 2: Respiratory pattern and airway resistance of AIRmin and AIRmax mice in the presence or absence of gallamine, a specific M2 receptor antagonist. Respiratory pattern to inhaled MCh was measured using noninvasive method in AIRmin (a) and AIRmax (b) mice. Airway resistance was measured by invasive method in AIRmin (c) and AIRmax (b) mice. Measurements were performed in the presence (black symbols) or absence (open symbols) of gallamine, in response to increasing concentrations of MCh. Results are reported as Penh values (a-b). Penh data represent the means ± SEM of five mice per group and are representative of three experiments (unpaired -test, * as compared to PBS group).