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

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 response 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.