Effects of polyunsaturated fatty acids on cardiac voltage-activated K(+) currents in adult ferret cardiomyocytes .

Abstract

This study was carried out in adult ferret cardiomyocytes to investigate the effects of the n-3 polyunsaturated fatty acids (PUFAs) on voltage-gated K(+) currents. We report that the two outward K(+) currents: the transient outward K(+) current (I(to)) and the delayed rectifier K(+) current (I(K)), are both inhibited by the n-3 PUFAs, while the inwardly rectifying K(+) current (I(K1)) is unaffected by the n-3 PUFAs. Docosahexaenoic acid (C22:6n-3, DHA) produced a concentration dependent suppression of I(to) and I(K) in adult ferret cardiomyocytes with an IC(50) of 7.5 and 20 micromol/L, respectively; but not I(K1). In addition, eicosapentaenoic acid (C20:5n-3, EPA) had the effects on the three K(+) channels similar to DHA. Arachidonic acid (C20:4n-6, AA) at 5 or 10 micromol/L, after an initial inhibitory effect on I(K), caused an activation of I(K),AA which was prevented by pretreatment with indomethacin, a cyclooxygenase inhibitor. Monounsaturated and saturated fatty acids, which are not antiarrhythmic, lack the effects on these K(+) currents. Our results demonstrate that the n-3 PUFAs inhibit cardiac I(to) and I(K) with much less potency compared to their effects on cardiac Na(+) and Ca(2+) currents as we reported previously. This inhibition of the cardiac ion currents by the n-3 PUFAs may contribute to their antiarrhythmic actions.

Cite this paper

@article{Xiao2002EffectsOP, title={Effects of polyunsaturated fatty acids on cardiac voltage-activated K(+) currents in adult ferret cardiomyocytes .}, author={Yong-fu Xiao and James P . Morgan and Alexander Leaf}, journal={Sheng li xue bao : [Acta physiologica Sinica]}, year={2002}, volume={54 4}, pages={271-81} }