An agent that releases basophil and mast cell histamine but blocks cyclooxygenase and lipoxygenase metabolism of arachidonic acid inhibits immunoglobulin E-mediated asthma in rhesus monkeys

An inhibitor of the lipoxygenase and cyclooxygenase pathways of arachidonic acid metabolism, BW755C, was evaluated with the rhesus monkey model of IgE-mediated asthma. BW755C was found to release histamine from human and rhesus peripheral blood leukocytes and rhesus bronchial lavage cells. BW755C did not induce a rhesus airway response but inhibited antigen-induced airway changes in pulmonary resistance and dynamic compliance. The results demonstrated that a lipoxygenase and cyclooxygenase inhibitor that is a histamine releaser may inhibit some pulmonary function abnormalities of an IgE-mediated response and suggested that histamine has a minor role as a stimulator of airway reaction in this model. This was supported by studies showing failure of the histamine H1 blocker pyrilamine maleate to inhibit the antigen-induced airway response. Although BW755C has been shown to be a lipoxygenase and cyclooxygenase inhibitor, it is not established that the inhibiting action of this agent on an antigen-induced airway response is due to an effect on arachidonate metabolism in the lung.