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Compartmentation of energy metabolism in atrial myocardium of patients undergoing cardiac surgery.

Abstract : The parameters of oxidative phosphorylation and its interaction with creatine kinase (CK)- and adenylate kinase (AK)-phosphotransfer networks in situ were studied in skinned atrial fibers from 59 patients undergoing coronary artery bypass surgery, valve replacement/correction and atrial septal defect correction. In atria, the mitochondrial CK and AK are effectively coupled to oxidative phosphorylation, the MM-CK is coupled to ATPases and there exists a direct transfer of adenine nucleotides between mitochondria and ATPases. Elimination of cytoplasmic ADP with exogenous pyruvate kinase was not associated with a blockade of the stimulatory effects of creatine and AMP on respiration, neither could it abolish the coupling of MM-CK to ATPases and direct transfer of adenine nucleotides. Thus, atrial energy metabolism is compartmentalized so that mitochondria form functional complexes with adjacent ATPases. These complexes isolate a part of cellular adenine nucleotides from their cytoplasmic pool for participating in energy transfer via CK- and AK-networks, and/or direct exchange. Compared to atria in sinus rhythm, the fibrillating atria were larger and exhibited increased succinate-dependent respiration relative to glutamate-dependent respiration and augmented proton leak. Thus, alterations in mitochondrial oxidative phosphorylation may contribute to pathogenesis of atrial fibrillation.
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Journal articles
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https://www.hal.inserm.fr/inserm-00391044
Contributor : Sarah Hamant <>
Submitted on : Wednesday, June 3, 2009 - 11:52:16 AM
Last modification on : Wednesday, July 15, 2020 - 9:10:04 AM

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  • HAL Id : inserm-00391044, version 1
  • PUBMED : 15792353

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Evelin Seppet, Margus Eimre, Nadezhda Peet, Kalju Paju, Ehte Orlova, et al.. Compartmentation of energy metabolism in atrial myocardium of patients undergoing cardiac surgery.. Molecular and Cellular Biochemistry, Springer Verlag, 2005, 270 (1-2), pp.49-61. ⟨inserm-00391044⟩

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