Document Detail

The role of the carotid chemoreceptors in the control of breathing during exercise.
MedLine Citation:
PMID:  8183097     Owner:  NLM     Status:  MEDLINE    
Our objective was to gain insight into the role of the carotid chemoreceptors (CC) in the exercise hyperpnea. Humans and ponies were studied at rest and during submaximal exercise breathing room air. In healthy humans, alveolar ventilation (VA) was tightly matched to CO2 production (CO2) resulting in PaCO2 deviating during exercise less than 1-2 mm Hg from rest. In contrast, ponies' VA increased proportionately more than VCO2 during exercise resulting in a workload dependent hypocapnia. Attenuating CC activity through hyperoxia had no effect on exercise PaCO2 of humans but hyperoxia accentuated the exercise hypocapnia of ponies. Similarly, CC denervation accentuated the exercise hypocapnia of ponies. Healthy humans were also studied while external airway resistance was increased, which, while breathing room air, resulted in a workload dependent hypercapnia, and this hypercapnia was accentuated by hyperoxia. Finally, a majority of asthmatic humans studied were hypercapnic during exercise while breathing room air and the hypercapnia was accentuated by hyperoxia. We conclude that the CC do not provide a primary drive for the exercise hyperpnea but they "fine tune" VA to minimize disruptions of arterial blood gases. In healthy humans, attenuating CC activity has no effect on PaCO2 because the primary VA drive is closely matched to VCO2.
H V Forster; L G Pan
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Publication Detail:
Type:  Journal Article; Research Support, U.S. Gov't, Non-P.H.S.; Research Support, U.S. Gov't, P.H.S.; Review    
Journal Detail:
Title:  Medicine and science in sports and exercise     Volume:  26     ISSN:  0195-9131     ISO Abbreviation:  Med Sci Sports Exerc     Publication Date:  1994 Mar 
Date Detail:
Created Date:  1994-06-15     Completed Date:  1994-06-15     Revised Date:  2008-11-21    
Medline Journal Info:
Nlm Unique ID:  8005433     Medline TA:  Med Sci Sports Exerc     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  328-36     Citation Subset:  IM; S    
Department of Physiology, Medical College of Wisconsin, Milwaukee.
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MeSH Terms
Carbon Dioxide / metabolism
Carotid Body / physiology*
Chemoreceptor Cells / physiology*
Exercise / physiology*
Heart Rate
Horses / physiology*
Oxygen Consumption
Respiration / physiology*
Grant Support
25739//PHS HHS
Reg. No./Substance:
124-38-9/Carbon Dioxide

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

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