MYOCARDIAL RECOVERY DURING POSTISCHEMIC REPERFUSION - OPTIMAL CONCENTRATIONS OF NA+ AND CA2+ IN THE REPERFUSATE AND PROTECTIVE EFFECTS OF AMILORIDE ADDED TO CARDIOPLEGIC SOLUTION
T. Yamada et al., MYOCARDIAL RECOVERY DURING POSTISCHEMIC REPERFUSION - OPTIMAL CONCENTRATIONS OF NA+ AND CA2+ IN THE REPERFUSATE AND PROTECTIVE EFFECTS OF AMILORIDE ADDED TO CARDIOPLEGIC SOLUTION, Heart and vessels, 10(6), 1995, pp. 310-317
The effects of Na+ and Ca2+ concentrations in the reperfusate on post-
ischemic myocardial recovery were examined. Also, the myocardial prote
ctive effects of amiloride, an inhibitor of the Na+/Ca2+ and Na+/H+ ex
change systems, added to cardioplegic solutions were assessed, using a
n isolated working rat heart perfusion system. Global myocardial ische
mia was induced by 30-min normothermic cardioplegic arrest, using St.
Thomas' solution. The concentration of Na+ in the reperfusate varied,
stepwise, from 75 to 145 mM/l, and that of Ca2+, from 0.1 to 2.5 mM/l.
In this study post-ischemic functional recovery was best at 110 mM/l
Na+ and 1.2-1.8 mM/l Ca2+ in the reperfusate. A significantly greater
postischemic functional recovery and a lower creatine kinase release w
ere observed when amiloride was added to the cardioplegic solution. Ca
2+ overload via Na+/Ca2+ and Na+/H+ exchange systems would, thus, appe
ar to be due, at least in part, to post-ischemic reperfusion injury.