Electroencephalographic effects of flurazepam in rabbits

Abstract

Electroencephalographic (EEG) effects of flurazepam were investigated in unanesthetized, unrestrained rabbits with chronic electrode implants and compared with those of diazepam. Flurazepam, at doses of 0.5~5 mg/kg i.v., induced a drowsy EEG pattern, i.e. high voltage slow waves in the cortex and amygdaloid complex and desynchronization of the hippocampal theta waves. In addition, low voltage fast waves were superimposed, especially on the cortical EEG. Flurazepam suppressed the EEG arousal responses induced not only by auditory stimulation but also by electrical stimulation of the mesencephalic reticular formation, posterior hypothalamus and centromedian thalamus. The EEG arousal response induced by i.v. injection of physostigmine was suppressed by flurazepam. Flurazepam depressed the photic driving response and the augmenting response. The recruiting response was slightly enhanced by flurazepam. The limbic afterdischarges elicited by either hippocampal or amygdaloid stimulation were suppressed by flurazepam. Flurazepam caused reductions of pressor responses to stimulation of the posterior hypothalamus and the mesencephalic reticular formation in anaesthetized rabbits. There was little or no effect on pressor responses to the injection of noradrenaline, carotid artery occulusion and asphyxia with flurazepam. In general, these effects of flurazepam were similar to those of diazepam, but the drug induced actions which differed from those of diazepam. © 1977, The Japanese Pharmacological Society. All rights reserved.