Inhibition by nedocromil sodium of early and late phase bronchoconstriction and airway cellular infiltration provoked by ovalbumin inhalation in conscious sensitized guinea‐pigs

Abstract
Bronchial challenge of ovalbumin‐sensitized conscious guinea‐pigs induced a triphasic reduction in specific airways conductance (sGaw) with maximal reductions being observed at 2, 17 and 72 h. accompanied by infiltration of the airways with neutrophils at 17 h and eosinophils at 17 and 72 h. Nedocromil sodium (10 mg ml−1) inhaled before challenge blocked the 2 and 17 h sGaw responses and the neutrophil influx. When inhaled 6 h after challenge, nedocromil inhibited the 17 h sGaw response but not neutrophil influx, suggesting that these are unrelated. The sGaw response and eosinophil accumulation at 72 h was also inhibited by nedocromil given at this time. Our findings correlate with the clinical effects of nedocromil, suggesting the guinea‐pig model may be useful for investigating the mechanism of action of anti‐asthmatic drugs.