Evolution of spirographic patterns in pulmonary bilaterally denervated dogs

One stage total bilateral pulmonary denervation produced in a group of 23 dogs an increase breathing frequency, an increase in the amplitude of respiration and a characteristic morphology of the spirographic pattern. Later in the evolution, these alterations returned to normal with the exeption of the amplitude of respiration which remained increased. This normalization was not accompanied by the reappearance of the Hering-Breuer reflux. Administration of an aerosol of acetylcholine after normalization of the spirographic pattern produced a temporary reappearance of the immediate postdenervation spirographic pattern. We postulate that in denervated lung a nervous plexus localized in the bronchi not related to the vagus might assume an important role in the regulation of respiration. One cannot exclude, however, the possibility that the reappearance of postdenervation pattern is due to stimulation of airways vagal receptors located in areas proximal to the level of the nervous section.