Effect of Ethanol on the Sodium and Potassium Conductances of the Squid Axon Membrane

Abstract

The effects of ethanol on squid giant axons were studied by means of the sucrose-gap technique. The membrane action potential height is moderately reduced and the duration sometimes shortened by ethanol in sea water. Voltage clamp experiments showed that ethanol in sea water reduced the maximum membrane conductances for sodium (g[image]Na) and potassium (g[image]K)- In experiments with multiple application of ethyl alcohol to the same spot of membrane, a reduction of g[image]Na to 82% and of g[image]K to 80% of their value in sea water was brought about by 3% ethanol (by volume) while 6% caused a decrease of g[image]Na to 59% and of g[image]K to 69%. Ethanol has no significant effect on the steady-state in-activation of g[image]Na (as a function of conditioning membrane potential) or on such kinetic parameters as Th or the time course of turning on gNa and g[image]K. It is concluded that ethanol mainly reduces gNa and gK in the Hodgkin-Huxley terminology.