Actions of Ethanol on Voltage-Sensitive Sodium Channels. Effects on Neurotoxin-Stimulated Sodium Uptake in Synaptosomes
Abstract
Exposure of rat brain synaptosomes to ethanol in vitro reduced the neurotoxin-stimulated uptake of sodium 22(+)Na. This effect of ethanol was concentration-dependent, occurred with concentrations of ethanol achieved in vivo and was fully reversible. The inhibitory effect of ethanol of neurotoxin- stimulated sodium uptake was due to a decrease in the maximal effect of the neurotoxins. Ethanol reduced the rate of batrachtoxin-stimulated sodium uptake when measured at 3,5 and 7 but not 10 or 20 sec after the addition of sodium 22 (+)Na. In a series of aliphatic alcohols, there was a good correlation between potency for inhibition of batrachotoxin-stimulated sodium 22 (+) 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 vernom-induced enhancement of batrachotoxin-stimulated sodium uptake. The inhibitory potency of teterodotoxin was also unaffected by ethanol. These results demonstrate that ethanol has an unhibitory effect on neurotoxin- stimulated sodium influx occuring in voltage-sensitive channels of brain tissue.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jan 01, 1985
- Accession Number
- ADA166853
Entities
People
- Michael J. Mullin
- Walter A. Hunt
Organizations
- Armed Forces Radiobiology Research Institute