The side of action of bronchodilating drugs (beta 2-stimulators) on antigen-induced bronchoconstriction.

The prophylactic effect of a sympathicomimetic drug (Fenoterol) was tested separately for the upper and the lower respiratory tract on 14 boxer dogs exposed to antigen challenge. In the lower airways, a restricted short-lasting diminution of bronchoconstriction was observed when both antigen and Fenoterol were administered to these airways. Administration of Fenoterol to the upper respiratory tract showed a long-lasting strong local effect in prevention of antigen-induced bronchoconstriction. There is a strong long-lasting effect of sympathicomimetic bronchodilators on the sensoric part of the reflex way into the airways. There is, with similar dosages, a weak short-lasting direct effect of these drugs on bronchial muscles.