Effects of acute and chronic ethanol administration on amino acid metabolism in rabbit brain and blood.

Acute administration of ethanol increased the cerebrocortical amino acids derived through the tricarboxylic acid cycle except for GABA and decreased the plasma alanine, valine, isoleucine, leucine, and phenylalanine whereas chronic administration of ethanol caused no significant changes in the cerebrocortical amino acids and increased the plasma glutamic acid, glutamine, glycine, and ornithine, with decreases in taurine and phenylalanine. Result of this experiment suggests that the CNS-depressant effect of ethanol is related to changes in the GABA system and increased uptake by the brain of the branched-chain amino acids while the development of tolerance to ethanol is associated with cellular adaptation in the CNS.