COMPARATIVE-STUDY ON THE EFFECTS OF EXOGENOUS PALMITATE AND ERUCATE ON INTRACELLULAR ELECTRIC PROPERTIES OF CULTURED BEATING HEART-CELLS

The effects of the palmitate- and erucate-enriched culture medium (0.2 mm) on the electrical and on the rhythmic activities of dissociated newborn rat cardiac cells maintained in vitro were analyzed. Both free fatty acids have no significant effect on the resting potential, but decrease the beating frequency. Palmitate shortens the action potential, while erucate elicits the opposite response. Palmitate and erucate induce specific alteration of the frequency-dependence of the action potential duration. Only K-erucate depresses overshoot potential level. It is suggested that the electrophysiological responses to high palmitate concentration are probably related to disturbed mitochondrial supply of cytoplasmic ATP, while the erucate would more specifically affect numerous membrane properties because of its chain length and unsaturated structure. The observed membrane potential changes may account for an arrhythmogenic effect of these fatty acids on the whole heart. © 1979.