Nasal secretion in ragweed-sensitized dogs: effect of leukotriene synthesis inhibition.

Allergic rhinitis is an inflammatory disease associated with local leukotriene release during periods of symptoms. Zileuton, a leukotriene synthesis inhibitor, is known to inhibit the release of leukotriene B4. Because we previously showed that leukotriene B4 is a potent mediator of neutrophil-dependent nasal secretion, we investigated whether Zileuton inhibited allergen-induced nasal secretion. Using a newly developed method for isolating and superfusing a nasal segment, we examined the effect of Zileuton on nasal secretion and neutrophil recruitment in ragweed-sensitized dogs. Instillation of ragweed into the nasal segment caused time-dependent increases in the volume of airway fluid and the recruitment of neutrophils. Zileuton prevented ragweed-induced neutrophil recruitment and nasal secretion. These results indicate that leukotrienes are important mediators of allergy-induced nasal secretion in dogs. Future clinical studies in allergic patients will determine whether there is a therapeutic role for leukotriene synthesis inhibitors in modulating neutrophil recruitment and hypersecretion in the nose.