Neuropharmacological profile of clobazam, a new 1',5'-benzodiazepine

The effect of the new 1,5-benzodiazepine clobazam on visual evoked potentials (VEP) and spontaneous EEG in the conscious rabbit and on spinal polysynaptic reflexes in the decerebrated cat was studied in comparison to the 1,4-benzodiazepine diazepam. Clobazam was half as potent as diazepam in depressing the amplitude of visual evoked potentials in the nonanaesthetized rabbit, whereas the depressing effect on spinal polysynaptic reflexes in the decerebrated cat was only 1/7 --1/30 of the diazepam effect. The action of clobazam and diazepam on VEP also showed differences in time course, i.e., the peak effect of clobazam lasted from 1 to 6 h after application, whereas the effect of diazepam appeared after 10 min and declined already after 1 h. Both compounds had similar effects on computer-analyzed spontaneous EEG in the rabbit (power spectrum analysis), with an increase of power in the beta-band (13-39Hz) and a decrease in the alpha (8-13 Hz) and theta (4-8Hz) bands.