The role of upper airways and of sensoric receptors on reflex bronchoconstriction.

The influence of bilateral transection of the nervi laryngici cranialis, laryngici caudalis and glossopharyngici on ACH and allergen-induced bronchoconstriction was tested in 15 dogs. In three dogs the free preparation of bilateral nervi laryngici cranialis was performed for control measurements. Partial transection of pulmonary left nervus vagus was performed in three dogs and compared to radical transection of the same nerve in three animals. Transection of the nervi laryngici cranialis as well as of the nervi glossopharyngici was followed by the inhibition of the allergen-induced bronchoconstriction. The bronchoconstriction following ACH challenge was not influenced by transection. Bronchoconstriction induced by allergen returned to the same values within three weeks after surgical intervention. Partial unilateral dissection of the vagus nerve on lung hilus shows a small decrease in bronchial constriction induced by allergen and by ACH. Complete unilateral dissection of the vagus nerve on the lung hilus reduced the bronchial constrictoric response to both substances significantly.