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001-es BibID:	BIBFORM040598
Első szerző:	Ebus, J.
Cím:	Effects of MgATP on ATP utilization and force under normal and simulated ischaemic conditions in rat cardiac trabeculae / J. Ebus, Z. Papp, R. Zaremba, G. J. Stienen
Dátum:	2001
ISSN:	0031-6768
Megjegyzések:	The dependency of ATP utilization and isometric force on [MgATP] was studied in skinned rat trabeculae under normal (pH 7.0) and simulated ischaemic (pH 6.2, 30 mM added Pi) conditions at 20+/-1 degrees C. At saturating [Ca2+], mean (+/-SEM) ATP utilization at 5 mM MgATP (A0) was 0.48+/-0.03 mM/s and force (F0) was 37+/-2 kN/m2. At 10 microM MgATP under normal conditions ATP utilization decreased gradually to 66+/-3% of A0, and force increased to 169+/-7% of F0. Under ischaemic conditions at 10 microM MgATP, ATP utilization decreased from 30+/-5% to 11+/-2% of A0 whereas force increased eightfold from 12+/-4% to 97+/-7% of F0. The [MgATP] at half-maximal ATP utilization (Km) under ischaemic conditions was 21+/-3 microM. At pH 7.0, Km was estimated to be less than 10 microM. These results show that tension cost decreases markedly with decreasing MgATP. Under ischaemic conditions parallel changes in Ca2+ sensitivity of force and ATP utilization were observed, corresponding to 1.3 pCa units. Reducing [MgATP] from 0.5 to 0.05 mM caused a modest reversal of this change in Ca2+ sensitivity. These changes in Ca2+ sensitivity are consistent with a marked reduction in active force and force-related ATP utilization during ischaemia but are insufficient to explain the ischaemic contracture on the basis of active force development.
Tárgyszavak:	Orvostudományok Klinikai orvostudományok idegen nyelvű folyóiratközlemény külföldi lapban
Megjelenés:	Pflugers Archiv-European Journal Of Physiology. - 443 : 1 (2001), p. 102-111. -
További szerzők:	Papp Zoltán (1965-) (kardiológus, élettanász) Zaremba, Ruud Stienen, Ger J. M.
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