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Titolo:
BOUND INORGANIC-PHOSPHATE AND EARLY CONTRACTILE FAILURE IN GLOBAL-ISCHEMIA
Autore:
ARMIGER LC; HEADRICK JP; JORDAN LR; WILLIS RJ;
Indirizzi:
GRIFFITH UNIV,ROTARY CTR CARDIOVASC RES NATHAN QLD 4111 AUSTRALIA GRIFFITH UNIV,ROTARY CTR CARDIOVASC RES NATHAN QLD 4111 AUSTRALIA UNIV AUCKLAND,DEPT PATHOL AUCKLAND NEW ZEALAND JAMES COOK UNIV N QUEENSLAND,DEPT CHEM & BIOCHEM TOWNSVILLE QLD 4811 AUSTRALIA
Titolo Testata:
Basic research in cardiology
fascicolo: 6, volume: 90, anno: 1995,
pagine: 482 - 488
SICI:
0300-8428(1995)90:6<482:BIAECF>2.0.ZU;2-L
Fonte:
ISI
Lingua:
ENG
Soggetto:
MAGNETIC-RESONANCE SPECTROSCOPY; RAT-HEART; ENERGY METABOLITES; CREATINE-PHOSPHATE; MYOCARDIUM; ISCHEMIA; NMR; ATP; MECHANISM; MUSCLES;
Keywords:
ISCHEMIA; BOUND INORGANIC PHOSPHATE; FREE INORGANIC PHOSPHATE; CONTRACTILE FAILURE; MAGNETIC RESONANCE;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Science Citation Index Expanded
Citazioni:
21
Recensione:
Indirizzi per estratti:
Citazione:
L.C. Armiger et al., "BOUND INORGANIC-PHOSPHATE AND EARLY CONTRACTILE FAILURE IN GLOBAL-ISCHEMIA", Basic research in cardiology, 90(6), 1995, pp. 482-488

Abstract

Inorganic phosphate (P-i) accumulates extremely rapidly in ischaemic heart muscle and intracellular binding of this metabolite may account for the precipitous loss of function seen at the onset of severe ischaemia. We have used P-31-NMR spectroscopy to measure the free cytosolic[P-i] and chemical assay techniques to measure total tissue P-i at 0,1, 2, 3, 5, and 12 min of complete global ischaemia in the isolated isovolumic rat heart. At zero time, the P-i assayed chemically was 30.77 +/- 5.52 mu mol/g dry wt (mean +/- SD, n = 7) whilst P-i assayed by NMR was 3.39 +/- 1.21 mu mol/g dry wt (n = 15). Thus, 27.38 mu mol/g dry wt of P-i was bound at a cytosolic [P-i] of 0.82 mM. After 12 min of ischaemia, 49.88 mu mol/g dry wt of Pi was bound at a cytosolic [P-i] of 4.11 mM. When all data were fitted, using a non-linear, least squares fit (p < 0.05), to the binding isotherm: Bound P-i = B'(max). [P-i]/(K'(d)+[P-i]), the apparent binding parameters K'(d) and B'(max) were estimated to be 1.1 +/- 0.6 mM and 64.0 +/- 10.2 mu mol/g dry wt respectively. During the first minute of global ischaemia when the rate-pressure product had decreased by 79 % of its pre-ischaemic value, bound Pi had increased by 58 % and free cytosolic [P-i] by 162 %. When functional and metabolite changes were expressed as a fraction of the total change which occurred during the 22-min ischaemic period, bound P-i had the profile most similar to the rate-pressure product. Both the amount of bound P-i and free cytosolic [P-i] correlated with loss of contractile function as the ischaemic period progressed. The results show that during ischaemia, P-i is bound progressively as free cytosolic[P-i] is increased as the result of high energy phosphate hydrolysis. While these results are consistent with the possibility that P-i binding may contribute to ischaemic contractile failure, no molecular explanation for the possible effect of bound P-i on contraction has been proposed.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 04/12/20 alle ore 16:20:36