[Protective effect of 7-oxo-prostacyclin on myocardial calcium overload in the isolated rat heart]

The protective effect of a stable derivative of prostacyclin (7-oxo PGI2) was studied on the model of calcium overload (Ca2+ paradox) 48 h after i.m. administration of the drug in the dose of 50 micrograms/kg. In the isolated rat heart perfused at 37 degrees C and a constant perfusion pressure of 75 Torr (Langendorff preparation) Ca2+ paradox was induced by 3 min perfusion with calcium-free Krebs-Henseleit solution and a subsequent 10 min perfusion with a normal calcium-containing solution. The late protective effect of 7-oxo PGI2 was manifested by improved recovery of heart function (increase of contractility by 50%) and by better preservation of the content of macroergic phosphates (70% sigma ADN) during the Ca2+ repletion phase and of myocardial ultrastructure (sarcolemma) already during the Ca2+ depletion phase. The protective effect of 7-oxo PGI2 can be accounted for by stimulation of Na, K-ATPase activity, otherwise decreased during calcium depletion phase, and by the consequent prevention of alterations in sodium and calcium homeostasis. (Tab. 1, Fig. 4, Ref. 41.)