Figure 8.

Airway hyperresponsiveness. The airway resistance (R), after increasing concentrations of methacholine (MCh) (0–40 mg/ml), was measured via the forced oscillation technique (flexiVent), at the end of the one-month exposure period to either air (control) or waterpipe smoke (WPS) with or without GA administration (15% w/v in drinking water). Dose-response relationship of total respiratory system resistance to increasing doses of MCh (a). From the resistance MCh dose-response curve in (a), an index of airway responsiveness was calculated as the slope of the linear regression using 0–40 mg/ml concentrations (b). Data are mean ± SEM (n = 8-9).