Summary
The effects of ethanol (0.5 to 5 Vol.-%) on identified neurons ofAplysia californica have been studied with the techniques of intracellular voltage recording and voltage and current clamping. In the visceral ganglion ethanol hyperpolarizes one group of identified cells and depolarizes a second group. The depolarizations may be up to the level of complete inactivation and are blocked in sodium-free sea water. While ethanol causes no significant effect on membrane resistance, it reduces spike amplitude, especially the overshoot. This effect on the spike potential correlates in voltage clamp with reductions of both sodium and calcium components of the inward currents by up to 50%, while the delayed potassium outward current is unaffected. In contrast a fast outward potassium-dependent current observable in some cells is slowed and reduced by up to 20%. The relatively smaller reduction of this current in contrast to the strong effect on the inward currents produces shifts in a depolarizing direction of the apparent steady state inactivation curves of the inward current. Ethanol did not alter the rate of the development of inactivation but it doubled the recovery from the inactivation following a conditioning depolarization. All of the ethanol effects are dose-dependent over the concentration range of 0.5 to 5 Vol.-% and are completely reversible.
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This work includes part of the Doctoral Thesis submitted by M.C.B. to the Johann Wolfgang Goethe-Universität, Frankfurt a. M., and part was presented at the 39th meeting of the German Physiological Society (Pflügers Arch., 332, R66, 1972).
Partly supported by a grant from Fa. E. Merck, Darmstadt, FRG, to M.C.B.
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Bergmann, M.C., Klee, M.R. & Faber, D.S. Different sensitivities to ethanol of three early transient voltage clamp currents of aplysia neurons. Pflugers Arch. 348, 139–153 (1974). https://doi.org/10.1007/BF00586476
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DOI: https://doi.org/10.1007/BF00586476