Document Detail


ADP-regulation of mitochondrial free radical production is different with complex I- or complex II-linked substrates: implications for the exercise paradox and brain hypermetabolism.
MedLine Citation:
PMID:  9298709     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
In agreement with classic studies, succinate-supplemented rat and pigeon heart and nonsynaptic brain mitochondrial free radical production is stopped by ADP additions causing the stimulation of respiration from State 4 to State 3. Nevertheless, with Complex I-linked substrates, mitochondria produce free radicals in State 3 at rates similar or somewhat higher than during resting respiration. The absence of sharp increases in free radical production during intense respiration is possible due to strong decreases of free radical leak in State 3. The results indicate that Complex I is the main mitochondrial free radical generator in State 3, adding to its already known important generation of active oxygen species in State 4. The observed rate of mitochondrial free radical production with Complex I-linked substrates in the active State 3 can help to explain two paradoxes: (a) the lack of massive muscle oxidative damage and shortening of life span due to exercise, in spite of up to 23-fold increases of oxygen consumption together with the very low levels of antioxidants present in heart, skeletal muscle, and brain; (b) the presence of some degree of oxidative stress during exercise and hyperactivity in spite of the stop of mitochondrial free radical production by ADP with succinate as substrate.
Authors:
A Herrero; G Barja
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Journal of bioenergetics and biomembranes     Volume:  29     ISSN:  0145-479X     ISO Abbreviation:  J. Bioenerg. Biomembr.     Publication Date:  1997 Jun 
Date Detail:
Created Date:  1997-11-14     Completed Date:  1997-11-14     Revised Date:  2008-11-21    
Medline Journal Info:
Nlm Unique ID:  7701859     Medline TA:  J Bioenerg Biomembr     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  241-9     Citation Subset:  IM    
Affiliation:
Department of Animal Biology-II (Animal Physiology), Faculty of Biology, Complutense University, Madrid, Spain.
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MeSH Terms
Descriptor/Qualifier:
Adenosine Diphosphate / metabolism*
Animals
Brain / metabolism*,  ultrastructure
Columbidae
Electron Transport Complex II
Free Radicals / metabolism
Male
Mitochondria / metabolism*
Mitochondria, Heart / metabolism*
Multienzyme Complexes / metabolism*
Myocardium / metabolism
NAD(P)H Dehydrogenase (Quinone) / metabolism*
Oxidative Stress
Oxidoreductases / metabolism*
Oxygen Consumption
Physical Exertion / physiology*
Rats
Rats, Wistar
Succinate Dehydrogenase / metabolism*
Succinic Acid / metabolism
Chemical
Reg. No./Substance:
0/Free Radicals; 0/Multienzyme Complexes; 110-15-6/Succinic Acid; 58-64-0/Adenosine Diphosphate; EC 1.-/Oxidoreductases; EC 1.3.5.1/Electron Transport Complex II; EC 1.3.99.1/Succinate Dehydrogenase; EC 1.6.5.2/NAD(P)H Dehydrogenase (Quinone)

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


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