The activity of respiratory pump and upper airway muscles during
sleep onset.
Worsnop, Christopher, Amanda Kay, Robert Pierce, Young Kim, John
Trinder.
School of Behavioural Science, The University of Melbourne,
Parkville, Victoria. 3052, Australia, The Department of Respiratory
Medicine, Austin and Repatriation Medical Centre, Heidelberg,
Victoria. 3084, Australia
APStracts 5:0194A, 1998.
Ventilation () decreases at sleep onset. This change is initiated
abruptly at (-( EEG transitions. The aim of this study was to
determine the contributions of reduced activity in respiratory pump
muscles and upper airway (UA) dilator muscles to this change. Surface
EMGs over the diaphragm (DI) and intercostal (IC) muscles and fine
wire intramuscular electrodes in genioglossus (GG) and tensor
palatini (TP) were recorded in nine healthy young men. It was shown
that phasic DI and both phasic and tonic TP activities were lower
during ( than during ( activity. Breath-by-breath analysis of the
changes at (-( transitions during the sleep onset period showed a
number of changes. At (-( transitions phasic activity of DI, IC and
GG fell and rose again, and phasic and tonic activities of TP fell
and remained at low levels during (. With a state transition from (
to (, the phasic and tonic activities of the DI, GG and TP increased
dramatically. It is now clear that the fall in that occurs with sleep
is related to a fall in activities of both UA dilator muscles and
respiratory pump muscles.
Received 9 June 1997; accepted in final form 27 April 1998.
APS Manuscript Number A525-7.
Article publication pending Journal of Applied Physiology.
ISSN 1080-4757 Copyright 1998 The American Physiological Society.
Published in APStracts on 16 June 1998