Document Detail


Vagal and chemoreceptor influences on abdominal muscle activity in awake lambs during hypoxia.
MedLine Citation:
PMID:  8514684     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
The ventilatory response to hypoxia is a complex phenomenon involving several control mechanisms. We designed this study to examine the dynamic control of abdominal muscle expiratory electromyogram (EMG) activity during room-air breathing and hypoxia and then to analyze the relative contribution of the chemoreceptors and vagal afferents. We studied 12 11- to 22-day-old awake nonsedated lambs, six intact and six vagotomized. To assess the dynamic influence of peripheral chemoreceptors on abdominal muscle expiratory activity, we performed transient testing of peripheral chemoreceptor function (pure O2 and N2 inhalation, KCN injection). To assess the influence of central chemoreceptor afferents, we compared results obtained during hypocapnic and isocapnic 15-min hypoxic runs (fractional concentration of inspired O2 0.08) in each lamb. We also compared results obtained in intact and vagotomized lambs so that the importance of vagal afferents could be assessed. We consistently observed abdominal muscle expiratory EMG activity in each lamb, whether intact or vagotomized, during baseline room air breathing; further recruitment was observed during hypoxia. We also consistently observed abdominal muscle expiratory recruitment during hypocapnic hypoxia in each lamb, although it was significantly less marked than during isocapnic hypoxia. Our transient testing of peripheral chemoreceptor function showed, furthermore, that peripheral chemoreceptor afferents dynamically modulate abdominal muscle expiratory activity. Thus, during hypoxia in 11- to 22-day-old awake nonsedated lambs, increased afferent information from peripheral chemoreceptors forcefully enhances abdominal muscle expiratory activity.(ABSTRACT TRUNCATED AT 250 WORDS)
Authors:
J P Praud; E Canet; I Kianicka; C Gaultier; M Bureau
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Journal of applied physiology (Bethesda, Md. : 1985)     Volume:  74     ISSN:  8750-7587     ISO Abbreviation:  J. Appl. Physiol.     Publication Date:  1993 Apr 
Date Detail:
Created Date:  1993-07-19     Completed Date:  1993-07-19     Revised Date:  2008-11-21    
Medline Journal Info:
Nlm Unique ID:  8502536     Medline TA:  J Appl Physiol     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  1689-96     Citation Subset:  IM    
Affiliation:
Jeremy Rill Center, Sherbrooke University, Quebec, Canada.
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MeSH Terms
Descriptor/Qualifier:
Abdominal Muscles / innervation,  physiopathology*
Afferent Pathways / physiopathology
Animals
Anoxia / physiopathology*
Chemoreceptor Cells / drug effects,  physiopathology*
Electromyography
Potassium Cyanide / pharmacology
Respiratory Mechanics / physiology
Sheep
Vagotomy
Vagus Nerve / physiopathology*
Chemical
Reg. No./Substance:
151-50-8/Potassium Cyanide

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


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