Mice were made physically dependent on ethanol by a 3-day period of alcohol inhalation with small daily injections of pyrazole. During this treatment the concentrations of norepinephrine, dopamine and 5-hydroxytryptamine were increased in brain with concomitant decrease in gamma-aminobutyric acid, RNA and DNA. However, the monoamine concentrations showed complete regression to normal levels at the time of maximal withdrawal seizure when GABA level was still elevated above the control values. Brain RNA and DNA concentrations remained low at this period. During the recovery phase, the pattern of neuronal components was almost the same as was observed at maximal withdrawal seizures. Pyrazole by itself did not produce significant changes in concentrations of the neuronal components of brain.