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Titolo:
POSSIBLE ROLE OF PHOSPHOLIPASE-C IN THE INDUCTION OF CA2-PARADOX IN RAT-HEART()
Autore:
PERSAD S; VRBANOVA A; MEIJ JTA; PANAGIA V; DHALLA NS;
Indirizzi:
ST BONIFACE GEN HOSP,DIV CARDIOVASC SCI,351 TACHE AVE WINNIPEG R2H 2A6 MANITOBA CANADA ST BONIFACE GEN HOSP,DIV CARDIOVASC SCI,351 TACHE AVE WINNIPEG R2H 2A6 MANITOBA CANADA UNIV MANITOBA,DEPT PHYSIOL WINNIPEG R2H 2A6 MB CANADA UNIV MANITOBA,DEPT ANAT WINNIPEG R2H 2A6 MB CANADA
Titolo Testata:
Molecular and cellular biochemistry
fascicolo: 2, volume: 121, anno: 1993,
pagine: 181 - 190
SICI:
0300-8177(1993)121:2<181:PROPIT>2.0.ZU;2-7
Fonte:
ISI
Lingua:
ENG
Soggetto:
CALCIUM PARADOX; REPERFUSION; PHOSPHOINOSITIDES; PERFUSION; FAILURE; RELEASE; ENZYMES; SODIUM;
Keywords:
PHOSPHOINOSITIDE PATHWAY; PHOSPHOLIPASE-C; CA2+-PARADOX; HEART MEMBRANES; ALPHA-ADRENERGIC RECEPTORS;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Science Citation Index Expanded
Citazioni:
38
Recensione:
Indirizzi per estratti:
Citazione:
S. Persad et al., "POSSIBLE ROLE OF PHOSPHOLIPASE-C IN THE INDUCTION OF CA2-PARADOX IN RAT-HEART()", Molecular and cellular biochemistry, 121(2), 1993, pp. 181-190

Abstract

In order to investigate the involvement of phosphoinositide-specific phospholipase C (PLC), an enzyme associated with phosphoinositide signal transduction pathway, for the occurrence of Ca2+-paradox (loss of contractile activity associated with contracture), rat hearts perfused with Ca2+-free medium (I to 5 min) were reperfused (5 to 10 min) with medium containing 1.25 mM Ca2+. Crude membranes isolated from hearts perfused with Ca2+-free medium exhibited a significantly increased activity of PLC, whereas normal activity was detected in hearts reperfusedwith Ca2+-containing medium. A significant rise in PLC activity was observed at 1 min of Ca2+-free perfusion; maximal increase was seen at 4min of Ca2+-free perfusion. Minimal concentration of Ca2+ in the perfusion medium required for showing an increase in PLC activity was 10muM, whereas that required for the occurrence of Ca2+-paradoxic changes in heart function upon reperfusion was 50 muM. Perfusion of the heartswith Ca2+-free medium in the presence of low Na+ or at low temperature, which prevents the occurrence of Ca2+-paradox upon reperfusion. didnot prevent the increase in PLC activity. An increase during Ca2+-free perfusion similar to that seen for PLC was also observed for two other enzymes. namely the phosphatidylinositol (PI) 4-kinase and the PI-4-monophosphate (PIP) 5-kinase, which synthesize the PLC substrate, phosphatidylinositol 4,5-bisphosphate (PIP2). No alteration of the alpha-adrenoreceptors was observed after 5 min of Ca2+-free perfusion. On the other hand, the observed changes in PLC activity during Ca2+-free perfusion appear to be due to some redistribution of the enzyme in the myocardium. These results suggest a possible role of the phosphoinositide/PLC pathway in the induction of Ca2+-paradox via mechanisms which do not appear to be associated with changes in the characteristics of alpha-adrenergic receptors.

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Documento generato il 03/12/20 alle ore 14:55:28