| The heart as a working model to explore themes and strategies for anoxic survival in ectothermic vertebrates. | |
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MedLine Citation:
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PMID: 17337222 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
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Most vertebrates die within minutes when deprived of molecular oxygen (anoxia), in part because of cardiac failure, which can be traced to an inadequate matching of cardiac ATP supply to ATP demand. Cardiac power output (PO; estimated from the product of cardiac output and central arterial pressure and an indirect measure of cardiac ATP demand) is directly related to cardiac ATP supply up to some maximal level during both normoxia (ATP supply estimated from myocardial O(2) consumption) and anoxia (ATP supply estimated from lactate production rates). Thus, steady state PO provides an excellent means to examine anoxia tolerance strategies among ectothermic vertebrates by indicating a matching of cardiac glycolytic ATP supply and demand. Here, we summarize in vitro measurements of PO data from rainbow trout, freshwater turtles and hagfishes to provide a reasonable benchmark PO of 0.7 mW g(-1) for maximum glycolytic potential of ectothermic hearts at 15 degrees C, which corresponds to a glycolytic ATP turnover rate of about 70 nmol ATP g(-1) s(-1). Using this benchmark to evaluate in vivo PO data for hagfishes, carps and turtles, we identify two cardiac survival strategies, which in conjunction with creative waste management techniques to reduce waste accumulation, allow for long-term cardiac survival during anoxia in these anoxia-tolerant species. Hagfish and crucian carp exemplify a strategy of evolving such a low routine PO that routine cardiac ATP demand lies within the range of the maximum cardiac glycolytic potential. Common carp and freshwater turtles exemplify an active strategy of temporarily and substantially decreasing cardiac and whole body metabolism so that PO is below maximum cardiac glycolytic potential during chronic anoxia despite being quite close to this potential under normoxia. |
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Authors:
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A P Farrell; Jonathan A W Stecyk |
Publication Detail:
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Type: Journal Article; Research Support, Non-U.S. Gov't; Review Date: 2007-01-30 |
Journal Detail:
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Title: Comparative biochemistry and physiology. Part A, Molecular & integrative physiology Volume: 147 ISSN: 1095-6433 ISO Abbreviation: Comp. Biochem. Physiol., Part A Mol. Integr. Physiol. Publication Date: 2007 Jun |
Date Detail:
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Created Date: 2007-04-30 Completed Date: 2007-07-16 Revised Date: - |
Medline Journal Info:
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Nlm Unique ID: 9806096 Medline TA: Comp Biochem Physiol A Mol Integr Physiol Country: United States |
Other Details:
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Languages: eng Pagination: 300-12 Citation Subset: IM |
Affiliation:
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Faculty of Land and Food Systems, University of British Columbia, Vancouver, BC, Canada V6T 1Z4. farrellt@interchange.ubc.ca |
Export Citation:
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| MeSH Terms | |
Descriptor/Qualifier:
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Animals Anoxia / pathology* Cardiac Output Heart / physiology* Models, Biological* Survival Analysis Vertebrates / physiology* |
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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