Pentobarbital-induced sleep test

The initial screening for hypnotic effect of 3-carene sleep was done with pentobarbital-induced sleep [23]. Experiment was performed between 13:00 and 17:00 h, and the ICR mice were fasted for 24 h before the experiment to minimize the drowsiness induced by food. 3-Carene and zolpidem were administered orally (p.o.) to the ICR mice (n=10) 45 min before the pentobarbital injection (45 mg/kg, i.p.). After the injection intraperitoneally (i.p.) of pentobarbital, mice were placed in individual cages and observed for measurements of sleep latency and duration. The observers were blinded to the individual treatments. The mice were considered asleep if stayed immobile and lost its righting reflex when positioned on its back. The sleep latency was defined as the elapsed time from pentobarbital injection to onset of righting reflex loss. The sleep duration was defined as the difference in time between the loss and the recovery of the righting reflex.