title: Cricothyroid muscle electrical activity during respiration and apneas in lambs.
abstract: Respiratory function of the cricothyroid muscle (CT) is virtually unknown in the neonatal period. This study was aimed at assessing CT electrical activity (EMG) during respiration and central apneas in non-sedated lambs. Seven full-term and four preterm lambs were instrumented for polysomnographic recording, including EMG of the diaphragm, thyroarytenoid (TA, a glottal constrictor), posterior cricoarytenoid (PCA, the primary glottal dilator) and CT. Phasic CT EMG was usually observed during inspiration and late expiration, whereas phasic TA EMG was observed during early expiration. While TA EMG virtually disappeared in REM sleep, both inspiratory and expiratory CT EMG increased. Overall, while CT EMG was not frequently observed during central apneas in either full-term (10% of apneas, but never simultaneously with TA EMG) or preterm lambs (30% of apneas), it was associated with decreased lung volume and subglottal pressure when present alone or with PCA EMG. Our results concur with the assumption that CT behaves as a laryngeal dilator in the neonatal period.
authors.affiliation: Neonatal Respiratory Research Unit, Department of Pediatrics, University of Sherbrooke, 3001 12(e) avenue Nord, Fleurimont, Que., Canada J1H 5N4.
authors.forename: Nathalie
authors.initials: N
authors.lastname: Samson
authors.forename: Joëlle Rouillard
authors.initials: JR
authors.lastname: Lafond
authors.forename: François
authors.initials: F
authors.lastname: Moreau-Bussière
authors.forename: Philippe
authors.initials: P
authors.lastname: Reix
authors.forename: Jean-Paul
authors.initials: JP
authors.lastname: Praud
mesh_terms: D000200:Action Potentials / Q000502:physiology*; D000818:Animals; D000831:Animals, Newborn; D001049:Apnea / Q000473:pathology* / Q000503:physiopathology*; D004569:Electroencephalography; D004576:Electromyography / Q000379:methods; D007821:Laryngeal Muscles / Q000503:physiopathology*; D017286:Polysomnography / Q000379:methods; D047928:Premature Birth / Q000473:pathology / Q000503:physiopathology; D012119:Respiration; D034561:Sheep, Domestic