[Energy-related disorders of myocardial contractility in calcium overload of the cardiomyocytes].
Langendorff perfusion of euthyroid rat heart with 10 mM phosphocreatine (PCr) in Krebs-Henseleit solution in conditions of Ca2+-paradox significantly potentiated the development of contracture and produced a 4-fold increase in perfusion pressure as compared to heart contractility in PCr-free, but otherwise similar conditions. Similarly, in case of hyperthyroid myocardium, addition of PCr into hypoxic perfusate (glucose omitted) in the presence of supranormal extracellular Ca2+ (5.0 mM) irreversibly inhibited the restitution of resting tension and developed tension during aerobic reperfusion. In the same conditions, PCr did not modulate contractility of euthyroid myocardium. These results are consistent with Ruigrok's hypothesis (1978) that intracellular Ca2+ redistribution is energy-dependent, provided PCr can penetrate into cardiomyocytes and stimulate ATP-dependent accumulation of Ca2+ in mitochondria, leading to an impairment of energy production. It is concluded that PCr exerts its cardioprotective effect only in case of a reversible (acute) phase of ischemia.
Seppet
E K
EK
Kallikorm
A P
AP
Dzhavadov
S A
SA
Preobrazhenskiĭ
A N
AN
Lakomkin
V A
VA
D000818:Animals; D002118:Calcium / Q000378:metabolism* / Q000494:pharmacology; D004734:Energy Metabolism; D005260:Female; D008929:Mitochondria, Heart / Q000378:metabolism; D009200:Myocardial Contraction; D009206:Myocardium / Q000378:metabolism*; D051381:Rats; D011919:Rats, Inbred Strains
D002118:Calcium
Energeticheskaia zavisimost' narusheniĭ sokratitel'noĭ funktsii miokarda v usloviiakh kal'tsevoĭ peregruzki kardiomiotsitov.