Document Detail


Peripheral chemoreceptors determine the respiratory sensitivity of central chemoreceptors to CO(2).
MedLine Citation:
PMID:  20421288     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
We assessed the contribution of carotid body chemoreceptors to the ventilatory response to specific CNS hypercapnia in eight unanaesthetized, awake dogs. We denervated one carotid body (CB) and used extracorporeal blood perfusion of the reversibly isolated remaining CB to maintain normal CB blood gases (normoxic, normocapnic perfusate), to inhibit (hyperoxic, hypocapnic perfusate) or to stimulate (hypoxic, normocapnic perfusate) the CB chemoreflex, while the systemic circulation, and therefore the CNS and central chemoreceptors, were exposed consecutively to four progressive levels of systemic arterial hypercapnia via increased fractional inspired CO(2) for 7 min at each level. Neither unilateral CB denervation nor CB perfusion, per se, affected breathing. Relative to CB control conditions (normoxic, normocapnic perfusion), we found that CB chemoreflex inhibition decreased the slope of the ventilatory response to CNS hypercapnia in all dogs to an average of 19% of control values (range 0-38%; n = 6), whereas CB chemoreflex stimulation increased the slope of the ventilatory response to CNS hypercapnia in all dogs to an average of 223% of control values (range 204-235%; n = 4). We conclude that the gain of the CNS CO(2)/H(+) chemoreceptors in dogs is critically dependent on CB afferent activity and that CNS-CB interaction results in hyperadditive ventilatory responses to central hypercapnia.
Authors:
Gregory M Blain; Curtis A Smith; Kathleen S Henderson; Jerome A Dempsey
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Publication Detail:
Type:  Journal Article; Research Support, N.I.H., Extramural; Research Support, Non-U.S. Gov't     Date:  2010-04-26
Journal Detail:
Title:  The Journal of physiology     Volume:  588     ISSN:  1469-7793     ISO Abbreviation:  J. Physiol. (Lond.)     Publication Date:  2010 Jul 
Date Detail:
Created Date:  2010-07-02     Completed Date:  2010-10-21     Revised Date:  2011-08-01    
Medline Journal Info:
Nlm Unique ID:  0266262     Medline TA:  J Physiol     Country:  England    
Other Details:
Languages:  eng     Pagination:  2455-71     Citation Subset:  IM    
Affiliation:
The John Rankin Laboratory of Pulmonary Medicine, Department of Population Health Sciences, School of Medicine and Public Health, University of Wisconsin, Madison, WI, USA. gregoryblain@ymail.com
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MeSH Terms
Descriptor/Qualifier:
Animals
Blood Gas Analysis
Carbon Dioxide / blood,  physiology*
Carotid Body / blood supply,  physiology
Carotid Sinus / physiology
Central Nervous System / physiology*
Chemoreceptor Cells / physiology*
Denervation
Dogs
Electromyography
Female
Peripheral Nervous System / physiology*
Regional Blood Flow / physiology
Respiratory Mechanics / physiology
Respiratory Physiological Phenomena*
Tidal Volume / physiology
Chemical
Reg. No./Substance:
124-38-9/Carbon Dioxide
Comments/Corrections
Comment In:
J Physiol. 2010 Dec 15;588(Pt 24):4857-8   [PMID:  21173088 ]

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