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Titolo:
Short-term hibernation in adult cardiomyocytes is PO2 dependent and Ca2+ mediated
Autore:
Stumpe, T; Schrader, J;
Indirizzi:
Univ Dusseldorf, Dept Physiol, D-40225 Dusseldorf, Germany Univ Dusseldorf Dusseldorf Germany D-40225 , D-40225 Dusseldorf, Germany
Titolo Testata:
AMERICAN JOURNAL OF PHYSIOLOGY-HEART AND CIRCULATORY PHYSIOLOGY
fascicolo: 1, volume: 280, anno: 2001,
pagine: H42 - H50
SICI:
0363-6135(200101)280:1<H42:SHIACI>2.0.ZU;2-G
Fonte:
ISI
Lingua:
ENG
Soggetto:
EARLY CONTRACTILE FAILURE; SITU PORCINE HEART; FREE-ENERGY CHANGE; MYOCARDIAL HIBERNATION; INORGANIC-PHOSPHATE; MODERATE ISCHEMIA; ENDOTHELIAL-CELLS; DOWN-REGULATION; ATP-HYDROLYSIS; MECHANISM;
Keywords:
Oxystat system; oxygen; myocardial hibernation; energy status; partial pressure of oxygen;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Life Sciences
Citazioni:
41
Recensione:
Indirizzi per estratti:
Indirizzo: Schrader, J Univ Dusseldorf, Dept Physiol, Univ Str 1, D-40225 Dusseldorf,Germany Univ Dusseldorf Univ Str 1 Dusseldorf Germany D-40225 Germany
Citazione:
T. Stumpe e J. Schrader, "Short-term hibernation in adult cardiomyocytes is PO2 dependent and Ca2+ mediated", AM J P-HEAR, 280(1), 2001, pp. H42-H50

Abstract

The mechanism of myocardial hibernation, the reversible downregulation of contractile activity on reduction of coronary flow with unchanged cardiac energetics, is presently not understood. The oxygen consumption ((V) over dot O-2), shortening fraction (DeltaL), energy status [phosphocreatine (PCr),ATP, and adenosine and lactate release], and free intracellular Ca2+ concentration ([Ca2+](i)) were measured in isolated rat cardiomyocytes at precisely controlled ambient PO2 (Oxystat). When PO2 was reduced from 25 to 6 mmHg, (V) over dot O-2 decreased by 50%, while DeltaL was downregulated from 11.2 +/- 4.1 to 7.6 +/- 4.0%, and energy status was unchanged in the steady state (observation time 12 min). Only transiently PCr decreased, and lactate and adenosine release increased. Further reduction of PO2 (to 3 mmHg) reduced (V) over dot O-2 by 80%, decreased PCr by 35%, moderately increased adenosine and lactate release, and progressively reduced DeltaL by 50% (to 5.6 +/- 3.3%). All parameters fully recovered during reoxygenation. PO2-dependent downregulation of DL was accompanied by a progressive reduction in systolic [Ca2+](i) (from 512 +/- 110 to 357 +/- 91 nmol/l at 6 mmHg and to 251+/- 69 nmol/l at 3 mmHg), whereas diastolic free [Ca2+](i) remained unchanged. Therefore, the mechanism of the reversible, PO2-dependent downregulation of contractile activity (myocardial hibernation) involves a substantial reduction of systolic calcium.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 30/11/20 alle ore 15:30:24