The Effects of Ethanol on ths Dog Purkinje Fiber

The effects of ehanol on the slope of slow depolarization, rising time, threshold potential, membrane conductance and plateau duration in the action potential of dog Purkinje fiber were studied by means of intracellular eleectrode techniques. The concentration of ehanol used in the present experiments was ianged netween 0.1% and 0.2%. It was observed that 0.1% ethanol lowered the beating frequency with the change of excitability at the level of threshold potential and shrtened the plateau because of increased membrane conductance for potassium ion. No significant changes in both the slow depolarization phase and rising time in the action potential were observed. It was discussed that ethanol was effective to inhibit the fibrillation by the mechanisms of elevating the threshlod in slow depolarization and of increasing the membrane conductance for potassium in plateau. This would be the reason why whanol is clinically useful for preventing the fibrillation which appears at warming0up stage after the operation of heart with hypothermia.