Ethanol enhancement of a calcium-activated potassium current in an identified molluscan neuron.

The effects of ethanol (5-50 mM) on cell F1 in the right parietal ganglion of Helix aspersa were studied electrophysiologically. In normal physiological solution ethanol depressed both spontaneous action potential duration and frequency by enhancement of the repolarization and after-hyperpolarization phases respectively. Depolarization under voltage-clamp in Na-free solution produced an outward current which peaked at about 100 ms and decayed to 75% of peak by 250 ms. Variation of external K+ and Ca2+ concentrations and blockade of Ca current with Co2+ suggests that this current, which is increased by more than 50% with 5 mM ethanol, is a Ca-activated K current. These results add to evidence that a variety of ion channels, depending on cell type and conditions, are affected by pharmacologically relevant concentrations of ethanol.