Effects of -3 polyunsaturated fatty acids on cardiac sarcolemmal Na /H exchange

Goel, Danny P., Thane G. Maddaford, and Grant N. Pierce. Effects of -3 polyunsaturated fatty acids on cardiac sarcolemmal Na /H exchange. Am J Physiol Heart Circ Physiol 283: H1688–H1694, 2002; 10.1152/ajpheart.00664. 2001.—Myocardial ischemia-reperfusion activates the Na /H exchanger, which induces arrhythmias, cell damage, and eventually cell death. Inhibition of the exchanger reduces cell damage and lowers the incidence of arrhythmias after ischemia-reperfusion. The -3 polyunsaturated fatty acids (PUFAs) are also known to be cardioprotective and antiarrhythmic during ischemia-reperfusion challenge. Some of the action of PUFAs may occur via inhibition of the Na /H exchanger. The purpose of our study was to determine the capacity for selected PUFAs to alter cardiac sarcolemmal (SL) Na /H exchange. Cardiac membranes highly enriched in SL vesicles were exposed to 10–100 M eicosapentanoic acid (EPA) or docosahexanoic acid (DHA). H -dependent 22Na uptake was inhibited by 30–50% after treatment with 50 M EPA or 25 M DHA. This was a specific effect of these PUFAs, because 50 M linoleic acid or linolenic acid had no significant effect on Na /H exchange. The SL vesicles did not exhibit an increase in passive Na efflux after PUFA treatment. In conclusion, EPA and DHA can potently inhibit cardiac SL Na /H exchange at physiologically relevant concentrations. This may explain, in part, their known cardioprotective effects and antiarrhythmic actions during ischemia-reperfusion.