Document Detail

NADH measurements in adult rat myocytes during simulated ischemia.
MedLine Citation:
PMID:  2058713     Owner:  NLM     Status:  MEDLINE    
In isolated adult rat myocytes, we tested the hypothesis that metabolic inhibition and simulated ischemia regulate the NADH/NAD+ redox couple with concomitant impairment of energy-dependent process, including contraction and maintenance of high-energy phosphate stores. We developed a method to examine the relationship among the redox couple, ATP content, and contractile performance in single cells under several conditions analogous to myocardial ischemia, with and without reperfusion. Myocytes were paced at 1 Hz while cell contraction and NADH fluorescence were determined simultaneously for single cells at 37 degrees C. Cells were exposed to cyanide and 2-deoxy-D-glucose (metabolic inhibition) or to metabolic inhibition plus 12 mM KCl and 20 mM lactate at pH 6.5 (simulated ischemia). Pyridine nucleotide fluorescence signals from single cells studied in this fashion could be modulated by metabolic inhibitors in a manner similar to that classically described for isolated mitochondria. Metabolic inhibition or simulated ischemia quickly produced maximal reduction of NAD+ to NADH. When cells were exposed to simulated ischemia for 10 min, then superfused with glucose-containing control buffer, 28% of cells exposed to conditions of simulated ischemia developed hypercontracture on reperfusion. Hypercontracture developed despite mitochondrial electron transport being reestablished. When myocyte suspensions in a cuvette were studied spectrofluorimetrically, the pyridine nucleotide fluorescence response to metabolic inhibitors was similar to that for a single cell. This permitted correlation of ATP determinations on cells in suspension with contractile and fluorescence measurements from single myocytes. In the absence of glycolysis there is correspondence among loss of electron transport, decline in high-energy phosphate concentration, and decline in contraction. Irreversible disruption of the electron transport process does not appear to be an early event in ischemic injury.
K Esumi; M Nishida; D Shaw; T W Smith; J D Marsh
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Publication Detail:
Type:  Journal Article; Research Support, U.S. Gov't, P.H.S.    
Journal Detail:
Title:  The American journal of physiology     Volume:  260     ISSN:  0002-9513     ISO Abbreviation:  Am. J. Physiol.     Publication Date:  1991 Jun 
Date Detail:
Created Date:  1991-08-01     Completed Date:  1991-08-01     Revised Date:  2007-11-14    
Medline Journal Info:
Nlm Unique ID:  0370511     Medline TA:  Am J Physiol     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  H1743-52     Citation Subset:  IM    
Department of Medicine, Brigham and Women's Hospital, Boston, Massachusetts 02115.
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MeSH Terms
Adenine Nucleotides / analysis
Adenosine Triphosphate / analysis
Cell Movement / drug effects
Coronary Disease / metabolism*,  pathology,  physiopathology
Cyanides / pharmacology
Deoxyglucose / pharmacology
Electron Transport / drug effects
Energy Metabolism / drug effects
Lactates / pharmacology
Mitochondria, Heart / metabolism
Myocardium / cytology*,  metabolism
NAD / analysis*,  metabolism
Potassium Chloride / pharmacology
Rats, Inbred Strains
Spectrometry, Fluorescence
Grant Support
Reg. No./Substance:
0/Adenine Nucleotides; 0/Cyanides; 0/Lactates; 154-17-6/Deoxyglucose; 53-84-9/NAD; 56-65-5/Adenosine Triphosphate; 7447-40-7/Potassium Chloride

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