Diazepam phase shifts the circadian clock of the field mouseMus booduga

Single 2h administration of diazepam (benzodiazepine) in 3.5% ethanol solution was found to evoke advance and delay phase shifts in the locomotor activity rhythm in the field mouseMus booduga. Through such pulsed administration of diazepam at various phases of circadian rhythm a phase response curve could be constructed. Phase advance occurred during early subjective day (CT 2) and phase delays were observed in the remaining phases. The shape of the diazepam phase response curve is similar to the general shape of the phase response curves generated by intraperitoneal injections of other benzodiazepines in hamsters. The phase shifting action of diazepam may be explained by its agonistic action on the neurotransmitter gamma-aminobutyric acid.