Temporal relation between energy metabolism and myocardial function during ischemia and reperfusion
- Griffith Univ., Nathan (Australia)
The purpose of the present investigation was to study the relation between energy metabolism and contractile function in the isovolumic guinea pig heart. {sup 31}P nuclear magnetic resonance spectroscopy was used to measure changes in the intracellular levels of creatine phosphate, ATP, inorganic phosphate, and pH during 2.43 min total global ischemia and 2.43 min reperfusion, with a time resolution of 9.7 s. From these data, cytosolic changes in the phosphorylation potential, (ATP)-to-(ADP) ratio, free-energy change of ATP hydrolysis, and concentration of free ADP were estimated. The simultaneous monitoring of functional and biochemical parameters allowed them to be directly correlated with respect to time and with respect to each other. No significant changes in ATP were detected at any time, but changes in all other biochemical data were highly correlated with changes in contractile function. Kinetic analysis, using a nonlinear least-squares fit of the experimental points, revealed that the changes in most parameters fitted monoexponential functions. Each parameter was ranked according to its half time, which revealed that (1) the phosphorylation potential was the only metabolic parameter to change at a rate faster than loss of contractile function during ischemia, and (2) all metabolic changes, with the exception of pH, led the recovery of contractile function during reperfusion, the most rapid change occurring in the free ADP concentration. It is concluded that the cytosolic phosphorylation potential controls the contractile function of the heart and that cytosolic free ADP is important in the control of mitochondrial oxidative phosphorylation.
- OSTI ID:
- 5028647
- Journal Information:
- American Journal of Physiology; (USA), Vol. 253:2; ISSN 0002-9513
- Country of Publication:
- United States
- Language:
- English
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ATP
METABOLISM
HEART
NUCLEAR MAGNETIC RESONANCE
ADP
CONTRACTION
GUINEA PIGS
PERFUSED TISSUES
PH VALUE
PHOSPHORUS 31
PHOSPHORYLATION
ANIMAL TISSUES
ANIMALS
BODY
CARDIOVASCULAR SYSTEM
CHEMICAL REACTIONS
ISOTOPES
LIGHT NUCLEI
MAGNETIC RESONANCE
MAMMALS
NUCLEI
NUCLEOTIDES
ODD-EVEN NUCLEI
ORGANIC COMPOUNDS
ORGANS
PHOSPHORUS ISOTOPES
RESONANCE
RODENTS
STABLE ISOTOPES
TISSUES
VERTEBRATES
550601* - Medicine- Unsealed Radionuclides in Diagnostics