DIRECT EFFECTS OF EXPECTORANTS ON THE TRACHEOBRONCHIAL SYSTEM IN VIVO

Abstract

Direct actions of expectorants and other secretagogues on the airway system in vivo were investigated. Bronchosecretory, bronchomotor and bronchovascular responses were determined in pentobarbital-anesthetized dogs, the bronchial artery of which was perfused with blood in situ. Pilocarpine and histamine had a direct strong stimulating effect on the airway secretory cells, and potassium iodide and ammonium chloride had a mild effect, while bromhexine had almost no stimulant effect on those cells. Potassium iodide and bromhexine produced a slight bronchoconstriction. Contribution of a transvascular transudate to the respiratory tract fluid produced by expectorants or other secretagogues was suggested to be quite small.