Document Detail

Intrinsic mechanical properties of the perfused armoured catfish heart with special reference to the effects of hypercapnic acidosis on maximum cardiac performance.
MedLine Citation:
PMID:  19376947     Owner:  NLM     Status:  MEDLINE    
The armoured catfish, Pterygoplichthys pardalis, is known to be extremely tolerant of environmental hypercarbia (elevated water CO(2) tensions), which occurs in their natural environment. In addition, previous studies have demonstrated that during exposure to hypercarbia, P. pardalis does not exhibit extracellular pH compensation and thus the heart and other organs must continue to function despite a severe extracellular acidosis. We used an in situ perfused heart preparation to determine the effects of an extracellular hypercapnic (elevated CO(2) in the animal) acidosis (1-7.5% CO(2)) on heart function, specifically cardiac output, power output, heart rate and stroke volume. The present study is the first to comprehensively examine cardiac function in an acidosis-tolerant teleost. When compared with control conditions, maximum cardiac performance was unaffected at levels of CO(2) as high as 5%, far exceeding the hypercapnic tolerance of other teleosts. Moreover, P. pardalis exhibited only a moderate decrease (approximately 35%) in cardiac performance when exposed to 7.5% CO(2), and full cardiac performance was restored in six out of seven hearts upon return to control conditions. Myocardial intracellular pH (pH(i)) was protected in situ, as has been found in vivo, and this protection extended to the highest level of CO(2) (7.5%) investigated. Thus, maintained heart function during a hypercapnic acidosis in P. pardalis is probably associated with preferential pH(i) regulation of the heart, but ultimately is not sufficient to prevent loss of cardiac function. Our findings suggest the need for further study to elucidate the mechanisms behind this remarkable cardiac hypercapnic tolerance.
Linda M Hanson; Daniel W Baker; Louise J Kuchel; Anthony P Farrell; Adalberto L Val; Colin J Brauner
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Publication Detail:
Type:  In Vitro; Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  The Journal of experimental biology     Volume:  212     ISSN:  0022-0949     ISO Abbreviation:  J. Exp. Biol.     Publication Date:  2009 May 
Date Detail:
Created Date:  2009-04-20     Completed Date:  2009-07-31     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  0243705     Medline TA:  J Exp Biol     Country:  England    
Other Details:
Languages:  eng     Pagination:  1270-6     Citation Subset:  IM    
Department of Zoology, University of British Columbia, Vancouver, BC, V6T 1Z4 Canada.
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MeSH Terms
Adaptation, Physiological
Carbon Dioxide / blood,  pharmacology*
Catfishes / physiology*
Heart / physiology*
Hydrogen-Ion Concentration
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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