Effect of drugs acting on monoaminergic and cholinergic systems on the quantified EEG of rats

Five different classes of drugs (clonidine: 0, 0.10, 0.30, 0.50 mg/kg; yohimbine: 0, 2, 4, 8 mg/kg; haloperidol: 0, 0.02, 0.04, 0.08 mg/kg; piracetam: 0, 150, 300, 600 mg/kg, and eserine: 0, 0.10, 0.30, 0.50 mg/kg) were studied on two cortical EEG derivations as well as a deep structure, the locus ceruleus in the rats. Each drug affected the EEG in its own particular manner. Clonidine significantly decreased frequency in the theta band (3.7-7.5 Hz) and increased it in the alpha band (7.6-13.5 Hz). A general significant increase in power was observed. Yohimbine's effects on the EEG varied according to the regions studied. There were significant modifications of power and frequency in the theta, alpha and beta bands in the three derivations studied. Notable effects of haloperidol were observed as an increase in power in all frequency bands at all doses administered particularly in the anteroparietal and posteroparietal derivations. In the locus ceruleus derivation, power was significantly increased at all doses only in the alpha and beta frequency bands. Concerning piracetam, while no significant effects were noted on the EEG frequency, this drug significantly increased EEG power in the posteroparietal and anteroparietal derivations. The most important effects are obtained at the lowest dose (150 mg/kg) administered. Finally, it was shown that eserine significantly decreased power in the delta bandwidth shortly after its administration. Afterwards, the power gradually regained its original level.