Document Detail

Redox behavior of cytochrome oxidase in the rat brain measured by near-infrared spectroscopy.
MedLine Citation:
PMID:  9390953     Owner:  NLM     Status:  MEDLINE    
Using near-infrared spectroscopy, we developed a new approach for measuring the redox state of cytochrome oxidase in the brain under normal blood-circulation conditions. Our algorithm does not require the absorption coefficient of cytochrome oxidase, which differs from study to study. We employed this method for evaluation of effects of changes in oxygen delivery on cerebral oxygenation in rats. When fractional inspired oxygen was decreased in a stepwise manner from 100 to <10%, at which point the concentration of oxygenated hemoglobin ([HbO2]) decreased by approximately 60%, cytochrome oxidase started to be reduced. Increases in arterial PO2 under hyperoxic conditions caused an increase in [HbO2], whereas further oxidation of cytochrome oxidase was not observed. The dissociation of the responses of hemogloblin and cytochrome oxidase was also clearly observed after the injection of epinephrine under severely hypoxic conditions; that is, cytochrome oxidase was reoxidized with increasing blood pressure, whereas hemoglobin oxygenation was not changed. These data indicated that oxygen-dependent redox changes in cytochrome oxidase occur only when oxygen delivery is extremely impaired. This is consistent with the in vitro data of our previous study.
Y Hoshi; O Hazeki; Y Kakihana; M Tamura
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Publication Detail:
Type:  Journal Article    
Journal Detail:
Title:  Journal of applied physiology (Bethesda, Md. : 1985)     Volume:  83     ISSN:  8750-7587     ISO Abbreviation:  J. Appl. Physiol.     Publication Date:  1997 Dec 
Date Detail:
Created Date:  1998-02-10     Completed Date:  1998-02-10     Revised Date:  2013-09-26    
Medline Journal Info:
Nlm Unique ID:  8502536     Medline TA:  J Appl Physiol (1985)     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  1842-8     Citation Subset:  IM    
Biophysics Group, Research Institute for Electronic Science, Hokkaido University, Sapporo 060, Japan.
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MeSH Terms
Brain / enzymology*
Electron Transport Complex IV / metabolism*
Hemoglobins / metabolism
Hypercapnia / physiopathology
Mitochondria, Heart / enzymology,  metabolism
Oxygen Consumption / physiology
Rats, Wistar
Spectroscopy, Near-Infrared
Reg. No./Substance:
0/Hemoglobins; EC Transport Complex IV

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