[Mechanisms of the conduction of cellular regulatory signals]

A rat isolated heart was used to demonstrate a protective effect of phosphocreatine (10 mM) in total normothermic ischemia (25 min) with subsequent reperfusion with the Krebs-Henzeleit solution and in cardioplegia in the St Thomas Hospital solution. The effect consisted in reduction in ischemic and reperfusion contraction and a 2-3-fold increase in cardiac output as compared with the control. A 20 per cent increase in the calcium content in the solution did not influence the phosphocreatine effect. Application of tocopheryl phosphate (0.1 microM) had no effect on the ischemic contraction but reduced diastolic pressure on reperfusion and provided a better maintenance of the cardiac parameters. The tocopheryl phosphate action increased when used in combination with phosphocreatine. The findings show that phosphocreatine slows down the development of ischemic damage and onset of irreversibility while antioxidants exert a protective effect by preventing a reperfusion damage to the heart.