Electroencephalographic and behavioral correlates in rats during repeated ethanol withdrawal syndromes.

Rats chronically implanted with electrodes in the amygdala, thalamus, hippocampus, and cortex were addicted twice, separated by an interval of 2 weeks, with 18 days of ethanol liquid diet. The diet consumption and the blood ethanol levels (BELs) were carefully controlled twice a day during both addictive phases. After ethanol removal the behavioral and electroencephalographic (EEG) changes were continuously monitored for 24 h. During each withdrawal the behavioral and EEG changes appeared at the same time, the EEG changes being of shorter duration. Behavioral and EEG changes (primarily in hippocampus) were more severe and of earlier onset during the second withdrawal. In spite of an ethanol liquid diet intake comparable to that of the first addiction, during the ethanol readdiction the BELs were found to fluctuate. The results support the hypothesis of an ethanol withdrawal potentiation through a mechanism of kindling of different brain areas related to the observed BEL fluctuations.