Indomethacin enhances response of human bronchus to antigen.

We studied the effect of indomethacin, an inhibitor of the cyclooxygenase pathway of arachidonic acid metabolism, on antigen-induced contraction of passively sensitized human bronchus in vitro. Incubation with indomethacin (3 microM) prior to antigen challenge produced significant enhancement of both the early (histamine-dependent) and late (SRS-A-dependent) phases of the contraction. Indomethacin potentiated anaphylactic histamine release from the bronchial tissue by approximately twofold but had no significant effect on basal tone or responsiveness to exogenous histamine. These data suggest that inhibition of the cyclooxygenase pathway results in potentiation of antigen-induced constriction of human bronchus principally through enhanced release of anaphylactic mediators from airway mast cells.