Effect of 5-lipoxygenase inhibitors on the anti-IgE-induced contraction of passively sensitized human bronchus in vitro.

We assessed the effect of 5-lipoxygenase inhibitors on the contraction of human bronchial ring segments passively sensitized with IgE in vitro. Contraction was induced by increasing doses of anti-IgE (0.01-0.5 micrograms/ml) in the presence of the antihistamine mepyramine. Zileuton and MK-886 (10 microM) significantly inhibited the dose-related contraction to anti-IgE as compared with solvent (DMSO). At the highest dose of anti-IgE used, contraction reached 10.3 and 9.6% of the maximal carbachol contraction, respectively, as compared with 30.3% for solvent. Maximal carbachol contraction was unaffected. These results suggest a potential beneficial effect of 5-lipoxygenase inhibitors in anaphylactic reactions in man.