Document Detail


Role of acidosis in early contractile dysfunction during ischemia: evidence from pHo measurements.
MedLine Citation:
PMID:  6496757     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
To investigate the contribution of acidosis to contractile dysfunction during early myocardial ischemia, miniature intramyocardial pH electrodes (0.2 mm tip diam) were used to correlate changes in extracellular pH (pHo) with tension in the isolated arterially perfused rabbit interventricular septum. A number of findings argue against acidosis as the major cause of contractile failure during early ischemia. During hypoxia without glucose present, the rate and pattern of tension decline was very similar to total ischemia, suggesting that a common mechanism is involved. Throughout the initial period in which tension declined by 50%, however, pHo increased in the six of eight preparations during hypoxia without glucose. During hypoxia with glucose present, tension fell less rapidly than during hypoxia without glucose despite a significantly greater fall in pHo in the former case. The maximal rate of relaxation (-dT/dt) was markedly more sensitive to ischemia, hypoxia, or exposure to inhibitors of aerobic metabolism (2,4-dinitrophenol and Na azide) than the maximal rate of force development (+dT/dt). In contrast, +dT/dt and -dT/dt decreased almost symmetrically during exposure to respiratory acidosis. During ischemia, the change in pHo associated with 50% reduction in tension was 0.11 +/- 0.04 units. During respiratory acidosis, this value was 0.45 +/- 0.02 units. From these observations we concluded that acidosis is unlikely to be a major factor in the early decline of tension during ischemia.
Authors:
J Weiss; G S Couper; B Hiltbrand; K I Shine
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't; Research Support, U.S. Gov't, P.H.S.    
Journal Detail:
Title:  The American journal of physiology     Volume:  247     ISSN:  0002-9513     ISO Abbreviation:  Am. J. Physiol.     Publication Date:  1984 Nov 
Date Detail:
Created Date:  1984-12-12     Completed Date:  1984-12-12     Revised Date:  2007-11-14    
Medline Journal Info:
Nlm Unique ID:  0370511     Medline TA:  Am J Physiol     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  H760-7     Citation Subset:  IM    
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MeSH Terms
Descriptor/Qualifier:
Acidosis / metabolism,  physiopathology*
Acidosis, Respiratory / metabolism,  physiopathology
Animals
Coronary Disease / metabolism,  physiopathology*
Glucose / metabolism
Hydrogen-Ion Concentration
Lactates / metabolism
Lactic Acid
Male
Microelectrodes
Myocardial Contraction*
Myocardium / metabolism
Oxygen / metabolism
Rabbits
Grant Support
ID/Acronym/Agency:
HL-7412/HL/NHLBI NIH HHS
Chemical
Reg. No./Substance:
0/Lactates; 50-21-5/Lactic Acid; 50-99-7/Glucose; 7782-44-7/Oxygen

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


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