Effect of unilateral vagus blockade on allergen-induced airway obstruction: results of short- and long-term experiments.

Abstract

Unilateral application of ascaris extract on segment bronchus as the influence of contralateral vagus blockade on reflex bronchoconstriction was studied on four boxer dogs in a first group (A) of experiments: ascaris extract was applied in liquid form directly through a catheter into the right segment bronchus. This application was repeated after contralateral vagus blockade and once more after its lavage. All the animals showed an increase of airway resistance under local application of ascaris extract which could not be avoided by contralateral central vagus blockade. In the second group (B) isolation of unilateral vagus for reproducible performance of blockade as a long-term model was investigated in three boxer dogs for 7 weeks and the influence of this method of unilateral vagus blockade on exposure to allergen aerosol was studied. The unilateral blockade of the nerve vagus was again always successful in decreasing the reflex bronchoconstriction following allergen inhalation. The effect of unilateral section of nervus vagus 3 weeks after this vagotomy was tested on two boxer dogs. Reflex bronchoconstriction following ascaris extract inhalation can be avoided by unilateral section of the nervus vagus the first time after section. Three weeks after this unilateral vagotomy, the reflex bronchoconstriction becomes managed by the remaining vagus trunk to the same degree as observed by bilateral intact vagi.