Document Detail

Synergistic effect of acidification and hypoxia: in vivo 31P-NMR and respirometric study in fishes.
MedLine Citation:
PMID:  8997378     Owner:  NLM     Status:  MEDLINE    
We used 31P nuclear magnetic resonance (31P-NMR) spectroscopy to measure intracellular pH (pHi) and high-energy phosphate levels of white muscle of the fish tilapia (Oreochromis mossambicus) during exposure to the stressors hypoxia and water acidification separately and simultaneously. The protocol for the graded hypoxia load was 100, 40, 30, 20, 10, 5, and 3% air saturation for 1 h at each level. For environmental acidosis the pH of the water was lowered from 7.6 to 4.0 over 6 h, with time of exposure approximately 11 h. All protocols were followed by 6 h of reoxygenation at 20 degrees C. We also measured total oxygen consumption of the animal. The results of this in vivo study revealed that environmental acidification had no effect on oxygen consumption, pHi, or phosphocreatine depletion. Hypoxia caused moderate changes in these parameters and fast and complete recovery during reoxygenation. In contrast, the combination of environmental acidosis and hypoxia resulted in 50% mortality, increased depletion of the phosphocreatine pool, and a retarded recovery of the pHi during reoxygenation compared with the group with hypoxia as a single stressor. The combination of environmental acidification and hypoxia has a more profound effect and works synergistically compared with the conditions imposed separately. To investigate whether an adaptation response occurred during chronic exposure to environmental acidification, animals were exposed for 6 wk to pH 4.0 before experimentation. The pHi in the white muscle dropped from 7.2 (control group) to 6.9 during this period, whereas no effect was found in the phosphorylated compounds and oxygen consumption. Therefore, it is concluded that no adaptation response occurs in animals exposed to long-term environmental acidosis.
V van Ginneken; G van den Thillart; A Addink; C Erkelens
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  The American journal of physiology     Volume:  271     ISSN:  0002-9513     ISO Abbreviation:  Am. J. Physiol.     Publication Date:  1996 Dec 
Date Detail:
Created Date:  1997-02-20     Completed Date:  1997-02-20     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  0370511     Medline TA:  Am J Physiol     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  R1746-52     Citation Subset:  IM; S    
Department of Biology, Gorlaeus Laboratories, Leiden, The Netherlands.
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MeSH Terms
Acids / pharmacology*
Anoxia / metabolism*,  mortality
Hydrogen-Ion Concentration
Muscles / drug effects*,  metabolism*
Oxygen / pharmacology
Oxygen Consumption / drug effects*
Phosphocreatine / metabolism
Tilapia / metabolism*
Reg. No./Substance:
0/Acids; 67-07-2/Phosphocreatine; 7723-14-0/Phosphorus; 7732-18-5/Water; 7782-44-7/Oxygen

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

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