Attributes of an alcohol-sensitive and an alcohol-insensitive transient potassium current in Aplysia neurons.
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 is 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.
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Worcester Foundation for Expermental Biology, Shrewsbury, Massachusetts 01545.
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D000818:Animals; D001048:Aplysia; D004305:Dose-Response Relationship, Drug; D000431:Ethanol / Q000494:pharmacology*; D005724:Ganglia / Q000187:drug effects; D008564:Membrane Potentials / Q000187:drug effects; D009420:Nervous System / Q000187:drug effects*; D009474:Neurons / Q000187:drug effects; D011188:Potassium / Q000378:metabolism*; D015221:Potassium Channels / Q000187:drug effects*; D009435:Synaptic Transmission / Q000187:drug effects*; D013696:Temperature
D015221:Potassium Channels; D000431:Ethanol; D011188:Potassium