Actions of ethanol on voltage-sensitive sodium channels: effects on neurotoxin-stimulated sodium uptake in synaptosomes

MJ Mullin and WA Hunt

Exposure of rat brain synaptosomes to ethanol in vitro reduced the neurotoxin-stimulated uptake of 22Na+. This effect of ethanol was concentration-dependent, occurred with concentrations of ethanol achieved in vivo and was fully reversible. The inhibitory effect of ethanol on neurotoxin-stimulated sodium uptake was due to a decrease in the maximal effect of the neurotoxins. Ethanol reduced the rate of batrachotoxin-stimulated sodium uptake when measured at 3, 5 and 7 but not 10 or 20 sec after the addition of 22Na+. In a series of aliphatic alcohols, there was a good correlation between potency for inhibition of batrachotoxin-stimulated 22Na+ uptake and the membrane/buffer partition coefficient, suggesting that a hydrophobic site in the membrane was involved in the action of the alcohols. Ethanol did not affect the scorpion venom-induced enhancement of batrachotoxin- stimulated sodium uptake. The inhibitory potency of tetrodotoxin was also unaffected by ethanol. These results demonstrate that ethanol has an inhibitory effect on neurotoxin-stimulated sodium influx occurring in voltage-sensitive sodium channels of brain tissue.

Volume 232, Issue 2, pp. 413-419, 02/01/1985
Copyright © 1985 by American Society for Pharmacology and Experimental Therapeutics

This article has been cited by other articles:

				S. I. Alekseev, A. S. Alekseev, and M. C. Ziskin Effects of Alcohols on A-Type K+ Currents in Lymnaea Neurons J. Pharmacol. Exp. Ther., April 1, 1997; 281(1): 84 - 92. [Abstract] [Full Text]