The brain marker proteins, D1, D2, and D3, localised to neuronal membranes, and mitochondrial and cytoplasmic marker proteins (MM and CM), were studied during 1-6 days (short term) intragastrically-induced severe ethanol intoxication and during 1 month (long-term) ethanol intoxication established by a liquid diet regimen. The concentrations of the same brain proteins were also measured during withdrawal from the ethanol intoxication periods. Three categories of effect were encountered: decreased concentration of brain marker proteins during severe short-term intoxication the effect being most marked for D3, possibly indicating degradation of mature synapses; increased concentration of proteins D2 and MM during withdrawal, the D2 changes possibly indicating formation of new synapses; increased concentration of D1 protein and MM during long-term intoxication. We suggest that the changes in brain marker proteins reflect dynamic changes of subcellular neuronal structures which may form a part of the basis of functional tolerance to and physical dependence upon ethanol or the reversion of these states after withdrawal of ethanol.