Figure 1.
Dose-response effect of Cl2 on respiratory responsiveness to methacholine. Mice were either unchallenged (Control; n = 6) or challenged with 100 (n = 6), 200 (n = 6) or 400 (n = 6) ppm Cl2 gas. After 24 h, total respiratory system resistance (A) and respiratory system elastance (B) in response to saline (Sal) and doubling doses of MCh were assessed using a small animal ventilator (FlexiVent). Baseline (Base) values obtained from untreated mice are shown for comparison. Mice treated with all three concentrations of Cl2 showed significantly higher respiratory system resistance and at 12.5, 25, and 50 mg/ml of MCh as compared with control. * p < 0.05, n = 6 per group.