Respiratory EMG activity of the posterior cricoarythenoid, cricothyroid and diaphragm muscles during sleep

Abstract

The respiratory activity (EMGs) of the posterior cricoarytenoid (PCA), cricothyroid (CT) and diaphragm (D) were examined during slow wave sleep (SWS) and paradoxical sleep (PS). Chronically implanted, free-to-move adult rats were used.In SWS, CT exhibited inspiratory or expiratory or inspiratory and expiratory bursts in each respiratory cycle. The latter was common during CO 2 (4%) breathing. PCA manifested phasic inspiratory discharges along with tonic respiratory activity. The latter was augmented by breathing CO 2. At onset of PS, inspiratory PCA and CT activity declined. In those PS epochs of irregular D activity, PCA and CT further declined during eye movements. In other PS epochs, D arrest coincided with co-activation of PCA and CT, occasionally CT activation alone, CO 2 breathing did not affect the above described during PS. In PS, loss of PCA and CT's inspiratory activity during rhythmic D activity may contribute to obstructive apne; PCA and CT co-activation with D arrest characterizes central type apnea.