Abstract
Ascaris suum extract inhalation causes bronchoconstriction in dogs. Following this reaction, the bronchi stay oversensitive against acetylcholine for at least 7 h. Electrical stimulation of the peripheral end of a nervus vagus after cutting supports the meaning that the bronchoconstriction will be caused mainly by challenge of sensory receptors. The reflex way runs through the nervus vagus. Sensitization of the bronchial tree means sensitization of the sensory receptors. Results of the arterial blood gases correspond to earlier results which showed two parts of the bronchial tree: the vagus-controlled part is mainly responsible for the airway resistance, the vagus-noncontrolled part is mainly responsible for the regulation of the ventilation/perfusion relationships.