Document Detail


Cardiorespiratory and tissue adenosine responses to hypoxia and reoxygenation in the short-horned sculpin Myoxocephalus scorpius.
MedLine Citation:
PMID:  15498961     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
Adenosine is a product of adenylate phosphate breakdown that can exert protective effects on tissues during energy limitation. Accumulation of cardiac adenosine under hypoxia is well documented in mammals but has not been shown in fish. Adenosine content was measured in heart and brain tissue from short-horned sculpin Myoxocephalus scorpius L. exposed to acute hypoxia and to graded hypoxia and reoxygenation at 8 degrees C. Cardiorespiratory parameters were recorded along with plasma lactate, K(+), Ca(2+) and Na(+) levels and their relationship to adenosine levels investigated. Sculpin exhibited a large bradycardia during hypoxia, with a concomitant drop in cardiac output that recovers fully with reoxygenation. Ventilation rate also declined with hypoxia, suggesting a depression of activity. Plasma lactate concentration was significantly elevated after 4 h at 2.0 mg l(-1) dissolved oxygen while K(+) levels increased during acute hypoxia. Adenosine levels were maintained in heart under acute and graded hypoxia. Brain levels fluctuated under hypoxia and showed no change with reoxygenation. It is concluded that a depression of cardiac activity in conjunction with an adequate anaerobic metabolism allow sculpin to avoid excessive adenosine accumulation under conditions of moderate hypoxia. Cardiac adenosine levels decreased and plasma K(+) levels and heart rate increased significantly at reoxygenation.
Authors:
T J Maccormack; W R Driedzic
Publication Detail:
Type:  Comparative Study; Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  The Journal of experimental biology     Volume:  207     ISSN:  0022-0949     ISO Abbreviation:  J. Exp. Biol.     Publication Date:  2004 Nov 
Date Detail:
Created Date:  2004-10-22     Completed Date:  2005-02-23     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  0243705     Medline TA:  J Exp Biol     Country:  England    
Other Details:
Languages:  eng     Pagination:  4157-64     Citation Subset:  IM    
Affiliation:
Ocean Sciences Centre, Memorial University of Newfoundland, St John's, NL, Canada A1C 5S7.
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MeSH Terms
Descriptor/Qualifier:
Adenosine / metabolism*
Animals
Anoxia / metabolism*
Brain / metabolism*
Calcium / blood
Chromatography, High Pressure Liquid
Fishes / metabolism,  physiology*
Lactic Acid / blood
Myocardium / metabolism*
Oxygen / metabolism
Potassium / blood
Respiratory Function Tests
Sodium / blood
Time Factors
Chemical
Reg. No./Substance:
50-21-5/Lactic Acid; 58-61-7/Adenosine; 7440-09-7/Potassium; 7440-23-5/Sodium; 7440-70-2/Calcium; 7782-44-7/Oxygen

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


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