Laryngeal and abdominal muscle electrical activity during periodic breathing in nonsedated lambs.

Kianicka, Irenej, Veronique Diaz, Sylvain Renolleau, Emmanuel Canet, and Jean-Paul Praud. Laryngeal and abdominal muscle electrical activity during periodic breathing in nonsedated lambs. J. Appl. Physiol. 84(2): 669–675, 1998.—We recently reported that glottic closure was present throughout central apneas in awake lambs. The present study tested whether glottic closure was also observed during periodic breathing (PB). We attempted to induce PB in 21 nonsedated lambs on return from hypocapnic hypoxia to room air. Airflow and thyroarytenoid (a laryngeal constrictor, n = 16), cricothyroid (a laryngeal dilator, n = 10), and abdominal (n = 9) muscle electrical activity (EMG) were monitored continuously. PB was observed in 16 lambs, with apneic phases in 8 lambs. Thyroarytenoid muscle EMG was observed at the nadir of PB, either throughout apnea or with prolonged expiration during the lowest respiratory efforts. Phasic inspiratory cricothyroid muscle EMG and phasic expiratory abdominal EMG disappeared at the na...