[Prevention of reperfusion-induced arrhythmia by Na+/H+ exchange block].
Using the isolated papillary muscle and rat hearts, perfused by Langendorf, the effects of the Na+/H+ exchange blocker, ethylisopropylamiloride (EIPA), on electrical activity and contractility, and induction of ischemic and reperfusion arrhythmias were studied. In the experiments with regional ischemia and reperfusion of an isolated heart (the ligation of the left anterior descending coronary artery for 10 minutes), EIPA (5 microM) effectively abolished reperfusion fibrillations, reducing the incidence of the long fibrillations from 60% (in the controls) to 8%, and increased nearly five-fold the time interval prior to their onset. Antiarrhythmic action of EIPA seems to be unconnected with the direct block of ionic channels, because 5 microM of this compound did not significantly change the action potential parameters, first derivative Vmax and the contractile response of the papillary muscle in normal conditions. The results obtained show a significant role of the postischemic activation of the Na+/H+ exchange in the initiation of reperfusion-induced arrhythmias and possible use of amiloride derivatives for their prevention.
Vasilets
L A
LA
Mokh
V P
VP
Khodorov
B I
BI
D000584:Amiloride / Q000031:analogs & derivatives* / Q000494:pharmacology; D000818:Animals; D000889:Anti-Arrhythmia Agents; D001281:Atrial Fibrillation / Q000517:prevention & control*; D006863:Hydrogen-Ion Concentration; D066298:In Vitro Techniques; D007474:Ion Exchange; D015428:Myocardial Reperfusion Injury / Q000517:prevention & control*; D009206:Myocardium / Q000378:metabolism*; D051381:Rats; D015222:Sodium Channels / Q000187:drug effects / Q000378:metabolism*
D000889:Anti-Arrhythmia Agents; D015222:Sodium Channels; D000584:Amiloride; C039614:ethylisopropylamiloride
Preduprezhdenie reperfuzionnykh aritmiĭ putem blokady Na+/H+ obmena.