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Application of negative expiratory pressure during expiration and activity of genioglossus in humans

Application of negative expiratory pressure during expiration and activity of genioglossus in humans Abstract The application of negative expiratory pressure (NEP) at end expiration has been shown to cause reflex-mediated activation of the genioglossus muscle in awake humans. To test whether a reflex contraction of pharyngeal dilator muscles also occurs in response to NEP applied in early expiration, the effect on genioglossus muscle reflex activity of NEP pulses of 500 ms, given 0.2 s after the onset of expiration and during the end-expiratory pause, was assessed in 10 normal awake subjects at rest. The raw and integrated surface electromyogram of the genioglossus (EMGgg) was recorded with airflow and mouth pressure under control conditions and with NEP ranging from −3 to −10 cmH 2 O. Intraoral EMGgg was also recorded under the same experimental conditions in two subjects. The application of NEP at the end-expiratory pause elicited a consistent reflex response of EMGgg in seven subjects with a mean latency of 68 ± 5 ms. In contrast, when NEP was applied at the onset of expiration, EMGgg reflex activity was invariably observed in only one subject. No relationship was found between steady increase or abrupt fall in expiratory flow and the presence or the absence of a reflex activity of genioglossus during sudden application of NEP at the beginning of expiration. Our results show that a reflex activity of genioglossus is elicited much more commonly during application of NEP at the end rather than at the onset of expiration. These findings also suggest that when NEP is applied in early expiration to detect intrathoracic flow limitation the absence of upper airways narrowing does not imply the occurrence of a reflex-mediated activation of genioglossus and vice versa. negative pressure expiration upper airway collapsibility Footnotes Address for reprint requests: C. Tantucci, Service de Pneumologie et Réanimation, Groupe Hospitalier Pitié-Salpêtrière, 17-47 Boulevard de l’Hôpital, 75651 Paris, Cedex 13, France. This work has been presented as a poster communication at the European Respiratory Society Annual Congress, Stockholm, Sweden, September 7–11, 1996. Copyright © 1998 the American Physiological Society http://www.deepdyve.com/assets/images/DeepDyve-Logo-lg.png Journal of Applied Physiology The American Physiological Society

Application of negative expiratory pressure during expiration and activity of genioglossus in humans

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Publisher
The American Physiological Society
Copyright
Copyright © 2011 the American Physiological Society
ISSN
8750-7587
eISSN
1522-1601
Publisher site
See Article on Publisher Site

Abstract

Abstract The application of negative expiratory pressure (NEP) at end expiration has been shown to cause reflex-mediated activation of the genioglossus muscle in awake humans. To test whether a reflex contraction of pharyngeal dilator muscles also occurs in response to NEP applied in early expiration, the effect on genioglossus muscle reflex activity of NEP pulses of 500 ms, given 0.2 s after the onset of expiration and during the end-expiratory pause, was assessed in 10 normal awake subjects at rest. The raw and integrated surface electromyogram of the genioglossus (EMGgg) was recorded with airflow and mouth pressure under control conditions and with NEP ranging from −3 to −10 cmH 2 O. Intraoral EMGgg was also recorded under the same experimental conditions in two subjects. The application of NEP at the end-expiratory pause elicited a consistent reflex response of EMGgg in seven subjects with a mean latency of 68 ± 5 ms. In contrast, when NEP was applied at the onset of expiration, EMGgg reflex activity was invariably observed in only one subject. No relationship was found between steady increase or abrupt fall in expiratory flow and the presence or the absence of a reflex activity of genioglossus during sudden application of NEP at the beginning of expiration. Our results show that a reflex activity of genioglossus is elicited much more commonly during application of NEP at the end rather than at the onset of expiration. These findings also suggest that when NEP is applied in early expiration to detect intrathoracic flow limitation the absence of upper airways narrowing does not imply the occurrence of a reflex-mediated activation of genioglossus and vice versa. negative pressure expiration upper airway collapsibility Footnotes Address for reprint requests: C. Tantucci, Service de Pneumologie et Réanimation, Groupe Hospitalier Pitié-Salpêtrière, 17-47 Boulevard de l’Hôpital, 75651 Paris, Cedex 13, France. This work has been presented as a poster communication at the European Respiratory Society Annual Congress, Stockholm, Sweden, September 7–11, 1996. Copyright © 1998 the American Physiological Society

Journal

Journal of Applied PhysiologyThe American Physiological Society

Published: Mar 1, 1998

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