[Effects of high and low doses of vitamins A and E on the excitability of frog cardiomyocytes].

The effects of complex vitamins A and E on electrophysiological characteristics was investigated on frog cardiomyocytes. Large doses of vitamins A and E decreased the steepness of the action potential (AP) front, decreased the spike amplitude, shortened the plateau, decreased the steepness in the last phase of AP-repolarization, and decreased the rest potential level but considerably increased overshoot. The Ap-duration decreased noticeably. Small doses of vitamins decreased the spike amplitude, shortened the plateau, decreased the Ap-duration. We assume that complex of vitamins A and E can affect the cardiomyocyte membrane transport function, mainly due to the suppression of the slow membrane channels. The AP-front increase is less steep under the influence of vitamins. It is shown that the 0-phase depolarization speed decreases due to the inhibition of sodium channels.