Document Detail


Regulation of cardiac energy turnover by coronary flow: a 31P-NMR study.
MedLine Citation:
PMID:  7505338     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
The response of cytosolic phosphates ([ATP], [PCr], [Pi] and [ADP]) in rat hearts retrogradely perfused with different oxidizable substrates to increased workload induced by elevated coronary flow (CF) or by addition of inotropic agents has been investigated. Hearts were perfused with glucose (11 mM), pyruvate (5 mM), lactate (3 mM) or a combination of glucose (5.5 mM) and acetate (5 mM), octanoate (0.1 mM) or beta-hydroxybutyrate (5 mM). The initial [ATP]/[ADP] ratio was highest in pyruvate and lactate perfused hearts. Increasing the coronary flow 1.7-fold (from c. 56 to 96 ml/min x g dry wt) resulted in an increase in pressure-rate product (PRP) by 36-52% without significant changes in cytosolic phosphates. Dichloroacetate (1 mM), ruthenium red (2.5 micrograms/ml), or pre-treatment with theophylline (1 mM, 30 min) had no effect either functional or metabolic response to elevated CF in glucose-perfused hearts. Isoproterenol (Iso, 0.1 microM) infusion at maximal coronary flows lead to further elevation of PRP value by 36-88% and the ratio of the maximal rate of relaxation to LV developed pressure ((-dP/dt)m/LVDP) increased two-fold. Simultaneously, [PCr] decreased by 18-30%, [Pi] increased two-fold and ADP increased by 20-90% resulting in reduction of [ATP]/[ADP] by half and ATP affinity (A(ATP) = -delta G(ATP)) by 2.4-3.8 kJ/mol. In hearts perfused with acetate, octanoate and hydroxybutyrate in the presence of glucose, Iso addition resulted in intracellular pH decrease by 0.03-0.07 U and increase in lactate extrusion 1.5-2 times. In hearts perfused with glucose alone, decrease in PRP induced by perfusate Ca2+ reduction was associated with increase in PCr and decrease in Pi levels. These data show that coordinated regulation of energy supply and demand exerted by coronary flow/perfusion pressure does not depend on the availability of reducing equivalents but is rather controlled by oxygen supply and stretch-activated factors.
Authors:
V V Kupriyanov; O V Korchazhkina; V L Lakomkin
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Publication Detail:
Type:  In Vitro; Journal Article    
Journal Detail:
Title:  Journal of molecular and cellular cardiology     Volume:  25     ISSN:  0022-2828     ISO Abbreviation:  J. Mol. Cell. Cardiol.     Publication Date:  1993 Oct 
Date Detail:
Created Date:  1994-01-21     Completed Date:  1994-01-21     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  0262322     Medline TA:  J Mol Cell Cardiol     Country:  ENGLAND    
Other Details:
Languages:  eng     Pagination:  1235-47     Citation Subset:  IM    
Affiliation:
Institute of Experimental Cardiology, Cardiology Research Center, Moscow, Russia.
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MeSH Terms
Descriptor/Qualifier:
Animals
Blood Flow Velocity / physiology
Coronary Circulation / drug effects,  physiology*
Dichloroacetate / pharmacology
Energy Metabolism / physiology*
Isoproterenol / pharmacology
Magnetic Resonance Spectroscopy*
Male
Myocardium / metabolism*
Ouabain / pharmacology
Phosphorus Isotopes
Rats
Rats, Wistar
Ruthenium Red / pharmacology
Theophylline / pharmacology
Chemical
Reg. No./Substance:
0/Phosphorus Isotopes; 11103-72-3/Ruthenium Red; 13425-80-4/Dichloroacetate; 58-55-9/Theophylline; 630-60-4/Ouabain; 7683-59-2/Isoproterenol

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


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