Relationship between the behavioral and electroencephalographic effects of chlorpromazine and fluphenazine in rats.

The effects of chlorpromazine and fluphenazine on behavior and electroencephalogram (EEG) have been studied in rats in order to find out whether quantitative surface EEG can be reliably used to assess the degree of hypnotic sedative activity of neuroleptic agents. It was found that fluphenazine is about 10 times more potent than chlorpromazine in depressing locomotor activity and variable-interval behavior of rats, while the two drugs were equally potent as regards their synchronizing action on the EEG. This is in accordance with the clinical observation that fluphenazine has less hypnotic side-effects than chlorpromazine and confirms that surface EEG can be a predictive test for hypnotic activity.