[Pharmacological investigations of 4'-fluoro-4-(4-methyl-peperidono)-butyrophenone with respect to its sedative and sleep-inducing properties (author's transl)].

: The butyrophenone melperone (Eunerpan) in mice and rats caused a prominetn inhibition of spontaneous activity, whereas cataleptogenic and apomorphine-antagonistic properties were less pronounced. In rats the sleep-cycle was altered: decrease of wakefulness, increase of slow-wave sleep and a moderate reduction of rapid eye movement-(REM) sleep. In contrast to thioridazine and chlorpromazine the effect lasted only for 4 h, followed by a slight REM rebound. In rabbits melperone caused a decrease of muscle tone and with somewhat higher doses an inhibition of the arousal-reaction. As seen by the computerized spontaneous cortical EEG, dosages below 1 mg/kg caused a shift of the dominant frequency from theta- to delta-rhythm and an increase of power. Therefore the neuropharmacological pattern of the butyrophenone melperone is closely related to those of thioridazine or chlorpromazine, without, however, having their long action.