Document Detail


Direct observation of radial intracellular PO2 gradients in a single cardiomyocyte of the rat.
MedLine Citation:
PMID:  9688918     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
The purpose of the present study was to directly visualize radial gradients of intracellular PO2 in a single individual cardiomyocyte isolated from the rat ventricle. Microspectrophotometry with the use of cytosolic myoglobin as an oxygen probe was conducted at 410 nm. When the quiescent cell was incubated with 1 microM carbonyl cyanide m-chlorophenylhydrazone to increase oxygen consumption approximately eightfold, gradual decreases in myoglobin oxygen saturation (SMb) were demonstrated toward the core of the cell, whereas these decreases disappeared when the cell was treated with 2 mM NaCN. These results highlighted the importance of diffusional oxygen transport in determining intracellular oxygenation in cardiac cells. From the measured SMb, we assessed the profile of radial changes in intracellular PO2 at the mean SMb comparable to that in vivo ( approximately 0.5). Quite steep PO2 gradients were demonstrated in the vicinity of the sarcolemma that were rapidly attenuated toward the cell core. These radial profiles of intracellular PO2 demonstrate the significance of myoglobin-facilitated diffusion of oxygen. Furthermore, the shallow gradients of PO2 near the center of the cell might arise from partial depression of oxygen consumption near the cell core.
Authors:
E Takahashi; K Sato; H Endoh; Z L Xu; K Doi
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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:  275     ISSN:  0002-9513     ISO Abbreviation:  Am. J. Physiol.     Publication Date:  1998 Jul 
Date Detail:
Created Date:  1998-08-27     Completed Date:  1998-08-27     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:  H225-33     Citation Subset:  IM    
Affiliation:
Department of Physiology, Yamagata University School of Medicine, Yamagata 990-9585, Japan.
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MeSH Terms
Descriptor/Qualifier:
Animals
Carbonyl Cyanide m-Chlorophenyl Hydrazone / pharmacology
Cells, Cultured
Cytosol / metabolism
Diffusion
Myocardium / cytology,  metabolism*
Myoglobin / metabolism
Oxygen / analysis,  metabolism*
Oxygen Consumption / drug effects
Partial Pressure
Rats
Rats, Sprague-Dawley
Sarcolemma / metabolism
Spectrophotometry / methods
Chemical
Reg. No./Substance:
0/Myoglobin; 555-60-2/Carbonyl Cyanide m-Chlorophenyl Hydrazone; 7782-44-7/Oxygen

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


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