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Genioglossus motor unit properties in a rat model of sleep apnoea
Author(s) -
O'Halloran Ken D.,
Bradford Aidan,
Jones James FX,
Edge Deirdre
Publication year - 2012
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.26.1_supplement.1147.7
Subject(s) - genioglossus , hypoxia (environmental) , dilator , anesthesia , medicine , basal (medicine) , motor unit , intermittent hypoxia , respiratory system , airway , endocrinology , chemistry , anatomy , oxygen , obstructive sleep apnea , organic chemistry , insulin
Intermittent hypoxia elicits plasticity in sensory and motor pathways involved in the control of breathing with potentially adaptive and maladaptive consequences for respiratory homeostasis. Chronic intermittent hypoxia (CIH) is a major feature of sleep‐disordered breathing. We sought to test the hypothesis that CIH alters pharyngeal dilator muscle motor unit properties. Adult male Wistar rats were exposed to 20 cycles of normoxia and hypoxia (5% O 2 at nadir; SaO 2 ~ 80%) per hour, 8 hours a day for 7 days (CIH, N=5) or sham treatment (N=5). Following gas treatments, rats were anaesthetized (urethane 1.5g/kg i.p.) and genioglossus (GG) muscle single motor unit potentials were recorded during quiet basal breathing. During basal breathing, the amplitude and duration of GG motor units was significantly different in sham vs. CIH‐treated rats (313±32μV vs. 430±46μV (amplitude) and 5.0±0.4ms vs. 3.4±0.2ms (duration); mean±SEM, Student's t test, p=0.0415 and 0.0013 respectively). The most common firing frequency of individual units determined from auto correlograms was significantly decreased (53±6Hz vs. 37±3Hz, sham vs. CIH, p=0.0318). Our results indicate that CIH causes remodelling in the central respiratory motor network with potential consequences for the physiological control of upper airway patency.