Document Detail

Changes in chemoreflex characteristics following acute carbonic anhydrase inhibition in humans at rest.
MedLine Citation:
PMID:  11187979     Owner:  NLM     Status:  MEDLINE    
The effect of carbonic anhydrase (CA) inhibition with acetazolamide (ACZ, 10 mg kg(-1) I.V.) on the peripheral and central chemosensitivity and breathing pattern was investigated in four women and three men aged 25 +/- 3 years using a modified version of Read's rebreathing technique. Subjects were exposed to dynamic increases in CO2 in hypoxic and hyperoxic backgrounds during control conditions and following acute CA inhibition. All manoeuvres were repeated twice and averaged for data analysis. The central chemoreflex sensitivities, estimated from the slopes of the ventilatory response to CO2 during hyperoxic rebreathing, increased following acute CA inhibition (control vs. ACZ treatment: 1.87 +/- 0.66 vs. 4.07 +/- 1.03 l x min(-1) (mmHg CO2)(-1), P < 0.05). The increased slope was reflected by an increase in the rate of rise of tidal volume and breathing frequency. Furthermore with ACZ, there was a left-ward shift of the ventilation vs. end-tidal PCO2 curve during hyperoxic hypercapnia but not hypoxic hypercapnia. The peripheral chemoreflex sensitivity was isolated by subtracting the hyperoxic slope (central only) from the hypoxic slope (central and peripheral). Following ACZ administration, the peripheral chemosensitivity was blunted (control vs. ACZ treatment: 3.66 +/- 0.92 vs. 1.33 +/- 0.46 l x min(-1) (mmHg CO2)(-1), P < 0.05). In conclusion, acute CA inhibition enhanced the central chemosensitivity to CO2 but diminished the peripheral chemosensitivity.
A Vovk; J Duffin; J M Kowalchuk; D H Paterson; D A Cunningham
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Experimental physiology     Volume:  85     ISSN:  0958-0670     ISO Abbreviation:  Exp. Physiol.     Publication Date:  2000 Nov 
Date Detail:
Created Date:  2001-01-12     Completed Date:  2001-03-01     Revised Date:  2008-11-21    
Medline Journal Info:
Nlm Unique ID:  9002940     Medline TA:  Exp Physiol     Country:  England    
Other Details:
Languages:  eng     Pagination:  847-56     Citation Subset:  IM    
School of Kinesiology, The University of Western Ontario, London, Canada.
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MeSH Terms
Acetazolamide / pharmacology*
Carbon Dioxide
Carbonic Anhydrase Inhibitors / pharmacology*
Chemoreceptor Cells / drug effects*
Hypercapnia / physiopathology
Hyperoxia / physiopathology
Reflex / drug effects*
Respiration / drug effects
Tidal Volume
Time Factors
Reg. No./Substance:
0/Carbonic Anhydrase Inhibitors; 124-38-9/Carbon Dioxide; 59-66-5/Acetazolamide

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