Ro5-4864 inhibits MC degranulation. (A) IgE-loaded BMMCs were pretreated for 20 min with the indicated concentrations of BDZs (Ro5-4864 and clonazepam) or a corresponding amount of DMSO and then either stimulated (white bars) with 20 ng/ml Ag (DNP-HSA) or left unstimulated (black bars) for another 20 min. Degranulation was measured by β-hexosaminidase assay. Each bar is the mean of duplicates ± SEM. Comparable results were obtained with cells from different cultures (n≥3). (B) IgE-loaded PMCs were treated as in (A) and degranulation was measured. Each bar is the mean of duplicates ± SEM. Marks of significance (“asterisks”) relate to the respective vehicle (DMSO) control. Each vehicle control contains the volume of DMSO necessary to dissolve the drugs in the respective BDZ samples. (C) Airway contractions to ovalbumin in rat precision-cut lung slices. On the left upper image airway under control condition is shown, whereas in the left lower image the airway has contracted to ovalbumin (10 μg/ml). On the right side kinetics of airway contractions to a single dose of OVA (10 μg/ml, n=5) in the presence and absence of Ro5-4864 (10 μM, 30 μM and 100 μM) is shown. Contractions are expressed as the decrease of airway area (%) compared to the initial airway area. Data (n=5) are presented as mean ± SEM. The area under the curve was compared by a one-way ANOVA followed by a Dunnett-test for multiple comparisons. All Ro5-4864 concentrations showed a statistical significance compared to control.