Cough reflex changes in local tracheitis.

The authors describe changes in the cough reflex in unanaesthetized cats with experimental local tracheitis. Inflammation was produced by a silk suture fixed in the trachea and cough was elicited by mechanical stimulation of different parts of the respiratory tract mucosa. The resultant cough values (the number of efforts, the intensity of the maximum effort and the intensity of the attack) were compared with the corresponding values in healthy cats. In animals with a tracheal suture, inflammation was confined to the trachea. The intensity of cough elicited by stimulation of this region increased significantly compared with normal (on the 15th to 17th day of inflammation), whereas cough elicited from the laryngopharyngeal and tracheobronchial region did not. On about the 20th day of inflammation the authors found a decrease in the intensity of the maximum effort of cough elicited from the inflamed part of the trachea and a decrease in the intensity of the maximum effort and the intensity of the coughing attack elicited from the laryngopharyngeal and tracheobronchial region. They assume that the decrease could have been due to the development of protective inhibition in central structures participating in integration of the cough reflex.