Document Detail


An assessment of central-peripheral ventilatory chemoreflex interaction using acid and bicarbonate infusions in humans.
MedLine Citation:
PMID:  7666375     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
1. The object of this study was to investigate the effect of central chemoreceptor stimulation on the ventilatory responses to peripheral chemoreceptor stimulation. 2. The level of central chemoreceptor stimulation was varied by performing experiments at two different levels of end-tidal CO2 pressure (PCO2). Variations in peripheral chemoreceptor stimulus were achieved by varying arterial pH (at constant end-tidal PCO2) and by varying end-tidal O2 pressure (PO2). 3. Two protocols were each performed on six human subjects. In one protocol ventilatory measurements were made during eucapnia, when the arterial pH was lowered from 7.4 to 7.3. The variation in pH was achieved by the progressive infusion of acid (0.1 M HCl). In the other protocol ventilatory measurements were made during hypercapnia, when the arterial pH was increased from 7.3 to 7.4. The variation in pH was achieved by the progressive infusion of 1.26% NaHCO3. In each protocol ventilatory responses were measured during euoxia (end-tidal PO2, 100 Torr), hypoxia (end-tidal PO2, 50 Torr) and hyperoxia (end-tidal PO2, 300 Torr), with end-tidal PCO2 held constant. 4. The increase in ventilatory sensitivity to arterial pH induced by hypoxia (50 Torr) was not significantly different between protocols (acid protocol, -104 +/- 31 l min-1 (pH unit)-1 vs. bicarbonate protocol, -60 +/- 44 l min-1 (pH unit)-1; mean +/- S.E.M.; not significant (n.s.)). The ventilatory sensitivity to hypoxia at an arterial pH of 7.35 was not significantly different between protocols (acid protocol, 14.7 +/- 3.3 l min-1 vs. bicarbonate protocol, 15.6 +/- 2.4 l min-1; mean +/- S.E.M.; n.s.). The results provide no evidence to suggest that peripheral chemoreflex ventilatory responses are modulated by central chemoreceptor stimulation.
Authors:
I D Clement; J J Pandit; D A Bascom; K L Dorrington; D F O'Connor; P A Robbins
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Publication Detail:
Type:  Clinical Trial; Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  The Journal of physiology     Volume:  485 ( Pt 2)     ISSN:  0022-3751     ISO Abbreviation:  J. Physiol. (Lond.)     Publication Date:  1995 Jun 
Date Detail:
Created Date:  1995-10-10     Completed Date:  1995-10-10     Revised Date:  2010-08-25    
Medline Journal Info:
Nlm Unique ID:  0266262     Medline TA:  J Physiol     Country:  ENGLAND    
Other Details:
Languages:  eng     Pagination:  561-70     Citation Subset:  IM    
Affiliation:
University Laboratory of Physiology, Oxford, UK.
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MeSH Terms
Descriptor/Qualifier:
Adolescent
Adult
Bicarbonates / administration & dosage,  pharmacology*
Chemoreceptor Cells / drug effects,  physiology*
Humans
Hydrogen-Ion Concentration
Infusions, Intravenous
Male
Oxygen Consumption / physiology
Reflex / drug effects,  physiology*
Respiratory Mechanics / drug effects,  physiology*
Grant Support
ID/Acronym/Agency:
//Wellcome Trust
Chemical
Reg. No./Substance:
0/Bicarbonates
Comments/Corrections

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


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