The location of sensoric bronchoconstricting receptors in the upper airways

The bronchoconstrictoric influence of allergen and acetylcholine aerosol was tested in 16 boxer dogs. The animals were exposed to these substances through a mask. The aerosol was also administered directly to three restricted areas of the trachea. Both substances induced a strong bronchoconstriction when administered through the mouth. Only the allergen showed a similar strong bronchoconstriction when administered to a restricted area in the upper third of the trachea.