Fig. 4.

Immediate hypersensitivity elicits the release of mast cell renin, resulting in ANG II-induced smooth muscle contraction in isolated guinea pig bronchial rings. Representative experimental traces of contractile responses measured in bronchial rings obtained from guinea pigs presensitized with rabbit anti-OA cytotropic IgG and challenged with OA (50 μg/ml) in the absence (control; n = 6) (A, C, and E) or presence of cromolyn (300 μM; n = 6) (B), BILA2157 (1 μM; n = 6) (D), or EXP3174 (100 nM; n = 6) (F). y axis, Contractile responses expressed as percentage of the response to K⁺ (80 mM). (G) Bar graph summarizing data from all experiments represented by traces in A–F. Bars indicate means ± SEM. *, **, Significantly different from control; P < 0.05 and 0.01, respectively, by one-way ANOVA with Dunnett's multiple-comparison test. W, wash.