Failure of aerosolized endothelin (ET-1) to induce bronchial hyperreactivity in the guinea pig

Aerosol administration of endothelin (ET-1) has been shown to provoke a potent bronchoconstriction in the guinea pig. We investigated whether or not, aerosolized ET-1 induces a bronchial hyperreactivity in the guinea pig. Aerosolized ET-1 (10 micrograms/ml for 60 min) did not alter the dose-response curve, established by successive aerosol administration of acetylcholine (ACh) 3-4 h and 18-24 h after challenge with the peptide. In a second protocol, aerosolized ET-1 (10 micrograms/ml for 3 min) induced, in anaesthetized guinea pigs a bronchopulmonary response but did not alter the dose-response curve to aerosolized ACh established 30 min after the challenge. These results suggest that ET-1 may participate to the early, but not the late alteration of the bronchopulmonary tone observed during pathophysiological conditions.