title: Genioglossus and breathing responses to airway occlusion: effect of sleep and route of occlusion.
abstract: We examined the effect of sleep state on the response of genioglossus muscle (EMGgg) activity to total airway occlusion applied at 1) nasal (N) airway [and thus exposing the upper airway (UAW) to pressure changes] and 2) tracheal (T) airway (thus excluding UAW from pressure changes). A total of 233 tests were performed during wakefulness (W), 98 tests in slow-wave sleep (SWS), and 72 tests in rapid-eye-movement (REM) sleep. Prolongation of inspiratory time (TI) of the first occluded effort occurred in all tests irrespective of behavioral state, with the greatest increase seen in awake N tests. Nasal tests augmented EMGgg activity in the first occluded breath and produced a linear increase in EMGgg during occlusion. The EMGgg activity at any given time during nasal occlusion in SWS was less than that recorded during W tests. There was a marked reduction in EMGgg response to N occlusion during REM sleep. The EMGgg activity during awake T tests was significantly less than that of N tests at any given time during occlusion. There was no relationship between the level of EMGgg activity and asphyxia in T tests performed during SWS and REM sleep. Nasal tests decreased the force generated by the inspiratory pump muscles and the central drive to breathing compared with T tests. These results confirm the important role of the UAW in regulating breathing pattern and indicate that both immediate and progressive load-compensating responses during nasal occlusion are influenced by information arising from the UAW.
authors: Department of Medicine, University of Sydney, New South Wales, Australia.
authors: F G
authors: FG
authors: Issa
authors: P
authors: P
authors: Edwards
authors: E
authors: E
authors: Szeto
authors: D
authors: D
authors: Lauff
authors: C
authors: C
authors: Sullivan
mesh_terms: D000402:Airway Obstruction / Q000503:physiopathology*; D000818:Animals; D004285:Dogs; D004576:Electromyography; D009132:Muscles / Q000503:physiopathology*; D012119:Respiration; D012890:Sleep / Q000502:physiology*; D012895:Sleep, REM / Q000502:physiology; D014059:Tongue / Q000503:physiopathology*