Alterations in the energy metabolism of the isolated perfused frog heart during calcium depletion and subsequent repletion

The changes in myocardial energy metabolism of isolated perfused Rana ridibunda hearts subjected to prolonged calcium depletion and reperfusion with calcium-containing medium were studied. Calcium-free perfusion resulted in an increase in the concentrations of glucose, glucose-6-phosphate, alpha-ket...

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Bibliographic Details
Published in:Journal of comparative physiology. B, Biochemical, systemic, and environmental physiology Biochemical, systemic, and environmental physiology, 1991-01, Vol.161 (1), p.85-92
Main Authors: TOURAKI, M, BEIS, I
Format: Article
Language:English
Subjects:
Animals
Biological and medical sciences
Biomarkers
Calcium - metabolism
Calcium - pharmacology
Citric Acid Cycle - drug effects
Energy Metabolism - drug effects
Fundamental and applied biological sciences. Psychology
Glycolysis - drug effects
Heart
In Vitro Techniques
Intracellular Fluid - enzymology
Myocardium - metabolism
Perfusion
Rana ridibunda
Vertebrates: cardiovascular system
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Summary:The changes in myocardial energy metabolism of isolated perfused Rana ridibunda hearts subjected to prolonged calcium depletion and reperfusion with calcium-containing medium were studied. Calcium-free perfusion resulted in an increase in the concentrations of glucose, glucose-6-phosphate, alpha-ketoglutarate and malate. The myocardial contents of high-energy phosphates were maintained while concentrations of key amino acids were significantly altered. During the reperfusion period the tissue high-energy phosphate content fell abruptly. A marked increase in glycolytic flux and lactate production was observed. The tissue contents of citric acid cycle intermediates and key amino acids decreased. Examination of the activities of marker enzymes during the calcium-free and reperfusion periods showed that only cytoplasmic enzymes are lost during reperfusion, while the activities of other enzymes remained unchanged. The results suggest that the fluxes of both glycolysis and the citric acid cycle are significantly altered during calcium depletion and following repletion in the amphibian heart. The major characteristics of calcium paradox-induced damage in Rana ridibunda heart are the depletion of high-energy stores, the impairment of mitochondrial oxidative metabolism, and a significant increase in anaerobic metabolism.
ISSN:0174-1578
1432-136X
DOI:10.1007/BF00258751