Physiol. Res. 52: 749-762, 2003

Activity of the Laryngeal Abductor and Adductor Muscles during Cough, Expiration and Aspiration Reflexes in Cats   


Department of Biophysics, Comenius University, Jessenius Faculty of Medicine, Martin, 1Department of Pathophysiology, Šafárik University, Faculty of Medicine, Košice and 2Department of Biology, Comenius University, Jessenius Faculty of Medicine, Martin, Slovak Republic

Received September 16, 2002
Accepted December 10, 2002 

We studied the temporal relationships and the patterns of electromyographic activities of the posterior cricoarytenoid and thyreoarytenoid muscles (laryngeal abductor and adductor), the diaphragm and abdominal muscles in anesthetized cats during mechanically induced tracheobronchial and laryngopharyngeal coughs, expiration and aspiration reflexes. The posterior cricoarytenoid muscle activity reached the maxima just before the peak of diaphragmatic activity in both types of cough and aspiration reflexes and slightly before the top of abdominal muscle activity in coughs and the expiration reflex. Thus, this muscle contributes to the inspiratory phase of coughs and aspiration reflex and also to the expulsive phase of coughs and the expiration reflex. The thyreoarytenoid muscle presented strong discharges in the compressive phase of coughs and expiration reflex (during the rising part of the abdominal muscle activity) and in the subsequent laryngoconstriction (following the diaphragmal and/or abdominal muscle activity) in all four reflexes. This muscle was also slightly activated at the beginning of the aspiration reflex. The existence of four phases of the cough reflex is also discussed.

Key words
Laryngeal muscles • Cough • Expiration and aspiration reflexes • Electromyogram • Cat

© 2003 by the Institute of Physiology, Czech Academy of Sciences