INHALED CROMOGLYCATE REDUCES AIRWAY NEUROGENIC INFLAMMATION VIA TACHYKININ ANTAGONISM

To determine whether sodium cromoglycate (SCG) inhibits airway neuroge nic inflammation and, if so, to elucidate the mechanism of its action, we studied plasma extravasation evoked by hypertonic saline in the ra t trachea by measuring the amount of extravasated Evans blue dye. Inha lation of hypertonic saline (5-15% NaCl) produced midrovascular leakag e, an effect that was reduced by pretreatment with SCG in a dose-depen dent manner. Inhaled SCG (10 mg/ml) for 2 min did not affect the basal vascular permeability, but significantly inhibited the 10% NaCl-induc ed plasma extravasation by 34%. SCG likewise inhibited the responses o f microvascular leakage to substance P aerosols, whereas it was withou t effect on those to platelet activating factor aerosols. These result s suggest that SCG inhibits airway neurogenic inflammation presumably via functional antagonism of tachykinins, and that this novel effect m ay be involved in the therapeutic efficacy of SCG in the treatment of airway inflammatory diseases including asthma.