Document Detail

Vagal feedback is essential for breathing in unanesthetized ground squirrels.
MedLine Citation:
PMID:  11282387     Owner:  NLM     Status:  MEDLINE    
The roles of vagal afferent feedback in terminating inspiration and modulating breathing pattern and ventilatory responses to hypoxia and hypercapnia were assessed in the golden-mantled ground squirrel, Spermophilus lateralis, during wakefulness and urethane anesthesia. Hypoxia increased ventilation primarily through increases in breathing frequency (f(R)) while hypercapnia increased ventilation primarily through increases in tidal volume (V(T)) in both anesthetized and unanesthetized animals. Vagotomy resulted in an increase in tidal volume, a decrease in breathing frequency and ventilation, and depressed ventilatory responses to both hypoxia and hypercapnia in anesthetized animals. In unanesthetized animals vagotomy produced a transient 'gasp-like' breathing pattern that rapidly progressed to a non-obstructive central apnea. These data indicate that vagal feedback shapes ventilation on a breath-by-breath basis during anesthesia and is essential for ventilation in unanesthetized animals. The mechanisms that transform the influences of vagal input on breathing between anesthetized and unanesthetized states remain unclear. Changes in breathing pattern induced by the removal of vagal feedback compromise chemoreflexes.
M B Harris; W K Milsom
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Respiration physiology     Volume:  125     ISSN:  0034-5687     ISO Abbreviation:  Respir Physiol     Publication Date:  2001 Apr 
Date Detail:
Created Date:  2001-04-03     Completed Date:  2001-06-28     Revised Date:  2009-11-11    
Medline Journal Info:
Nlm Unique ID:  0047142     Medline TA:  Respir Physiol     Country:  Netherlands    
Other Details:
Languages:  eng     Pagination:  199-212     Citation Subset:  IM    
Department of Zoology, University of British Columbia, 6270 University Boulevard, Vancouver, BC, V6T 1Z4, Canada.
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MeSH Terms
Acute Disease
Afferent Pathways / physiology
Anoxia / physiopathology
Chronic Disease
Hypercapnia / physiopathology
Respiratory Mechanics / physiology*
Sciuridae / physiology*
Vagus Nerve / physiology*
Wakefulness / physiology

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

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