Attributes of an Alcohol-sensitive and an Alcohol-insensitive Transient Potassium Current in Aplysia Neurons

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Abstract
We describe two subtypes of transient potassium current, IA, found in two identified cells within the nervous system of Aplysia. These subtypes of IA are differentially sensitive to ethanol, since the decay of current is significantly slowed in the presence of ethanol in one cell, while IA unaffected by ethanol at the same concentrations in the other cell. In this paper, we examine a number of parameters including temperature sensitivity of these different IAs. While both currents fulfill the criteria for being called IA, they are significantly different with respect to the kinetics of activation and inactivation, as well as recovery from inactivation. They do not differ significantly in the temperature sensitivity of a number of measured parameters, suggesting that ethanol and temperature do not act as a common locus; e.g., by affecting a bulk lipid membrane fluidity. In light of recent work describing the molecular biology of channels underlying IA, it is reasonable to assume that these IA subtypes reflect different underlying channels. This system may be useful for understanding the relationship of channel structure and function to ethanol action.