Abstract
Heman airway preparations at resting tone were relaxed with either the leukotriene synthesis inhibitor BAY x1005 (3 μM), chlorpheniramine (1 μM) or the thromboxane receptor antagonist BAY u3405 (0.1 μM). The response to anti-IgE (1:1000) was 58 ± 8% of acetylcholine pre-contraction (2.19 ± 0.28 g). Indomethacin (3 μM) enhanced the anti-IgE-induced contraction by 28%. The anti-IgE maximal response was not modified by either chlorpheniramine, BAY x1005 or BAY u3405. When the tissues were treated with either BAY xl005/indomethacin or BAY x1005/chlorpheniramine, the anti-IgE-induced contraction was reduced. In addition, in presence of BAY xl005/indomethacin/chlorpheniramine the response was completely blocked. These results suggest that mediatots released during anti-IgE challenge cause airway contraction which may mask the evaluation of the leukotriene component.