MYOCARDIAL PROTECTION BY ETHYL-ISOPROPYL AMILORIDE, A SPECIFIC NA+-H+ EXCHANGE INHIBITOR, FOLLOWING HEMORRHAGIC SHOCK

Background: Hemorrhagic shock and resuscitation is well known to result in myocardial dysfunction and injury. Stimulation of the Na+-H+ exchanger plays an important role in the pathway of myocardial injury. The purpose of the present study was to examine the protective effects of blocking the cardiac Na+-H+ exchange, using 100 mM ethyl-isopropyl amiloride (EIPA), a specific Na+-H+ exchanger blocker, on myocardial contractile function on ex vivo resuscitation of isolated rat heart following one hour of hemorrhagic shock. Methodology: Sprague- Dawley rats were assigned to hemorrhage, hemorrhage + EIPA, sham hemorrhage and sham hemorrhage + EIPA groups. Rats were hemorrhaged for one hour. Hearts were harvested and ex vivo treated and resuscitated by perfused in the Langendorff System. Myocardial function was determined. Results: The results showed that inhibition of the Na+-H+ exchanger using EIPA improved the post-resuscitation myocardial contractile function. Conclusion: Blocking the Na+-H+ exchanger using 100mM EIPA following 60 minutes of hemorrhagic shock improved myocardial function.