Influence of low concentrations of allergens on bronchial system.

The influence of Ascaris extract, applied during 1 h in low concentration as aerosol and intravenously, on the bronchial system and the potentiation of increase of airway resistance to acetylcholine (ACH) and histamine challenge caused by this kind of allergen exposure were studied in 13 dogs. All the animals presented no reaction by the allergen exposure itself but developed an increased response to ACH and histamine after this kind of allergen exposure. A control group of 4 dogs was submitted to saline solution aerosol and intravenous application. No change in response to the substances mentioned was observed. The airway response to cold air after concentrated and diluted Ascaris suum extract (AE) aerosol application was tested on 7 dogs. The response to cold air was only influenced after concentrated AE-aerosol exposure.