[Effect of etimizol, ethyrasol, and caffeine on the electrical activity of mollusk neurons].

In experiments on Limnae stagnalis neurons, ethymisol increased the AP duration while reducing the trace hyperpolarization and the rate of development of the AP descending phase. Ethymisol (10 mM/1) induced either hyperpolarization of neurons with an increase in membrane resistance or their depolarization (20 mM/1) with a decrease in membrane resistance. A drop in the medium temperature by 2-4 degrees C prevented the hyperpolarization. The ethymisol-induced hyperpolarization seems to be connected with a decrease in membrane permeability for sodium ions in resting conditions and with activation of electrogenic ion transport. The increase of extraneuronal potassium up to 4 mM/1 and depolarization induced by currents of 1-3 nA intensified the ethymisol effects. Ethymisol decreased efflux and influx of ions through membrane thus affecting the AP parameters. The effects of ethymisol also involved an increase of neurons excitability and intensification of synaptic activity. Neither ethyrasol nor caffein exerted these effects.