Figure 7: Indirect comparison in pulmonary gas trapping (upper panel) and enhanced pause (lower panel) of Positive and Negative Control mice produced by methacholine. For each method, intraand inter-study variability was assessed in nine experiments performed over approximately 6 months. Each point corresponds to an individual animal, and the horizontal bar represents the mean for each group. One hundred mice (Positive Controls, n=50 mice, and Negative Controls, n=50 mice) were used to examine methacholine-induced pulmonary gas trapping, while 142 mice (Positive Controls, n=72 mice, and Negative Controls, n=70 mice) were used to examine enhanced pause following methacholine. The percentages listed in each figure represent the relative increase in excised lung gas volume and enhanced pause values of Positive Control mice compared to Negative Control mice. Asterisks indicate significant difference (P<0.05) between the mean excised lung gas volume or mean enhanced pause values for Positive and Negative Control mice (from Stengel et al. [22]).