ObjectiveTo investigate whether rice bran oil rich in oryzanol has effects on pentobarbital-induced sleeping behaviors and locomotor activities in partial sleep-deprived mice.Methods Sixty mice were randomly divided into five groups (12 for each). Control and partial sleep deprivation (PSD) model groups were fed basic rodent chow with 8% soy-bean oil (oryzanol free). PSD-low oryzanol (PSD-lOZ), PSD-medium oryzanol (PSD-mOZ) and PSD-high oryzanol (PSD-hOZ) groups were fed basic rodent chow with 8% rice bran oil, containing 3000, 7000 and 15000 mg/kg of oryzanol, respectively for 25 d. The locomotor activities after PSD and the latency and duration of sleep induced by pentobarbital were determined. The contents of monoamines, as norepinephrine (NE), dopamine (DA) and serotonin (5-HT) were measured by HPLC-ESI-MS/MS.Results Immediately after PSD, the locomotor activities in PSD model group were decreased compared with the control group (P< 0.05). The PSD-mOZ and PSD-hOZ groups had higher locomotor activities than the PSD model group (bothP< 0.05). The latency of sleep in the PSD-mOZ group and PSD-hOZ group were both decreased when compared with the PSD model group (bothP< 0.05). Linear regression showed that the duration of sleep time increased in dose dependent manner with the contents of oryzanol in rice bran oil (P=0.05). The PSD model group had lower level of NE, DA and 5-HT when compared with the control group (allP<0.05). Supplementation of high contents of oryzanol in rice bran oil may prevent the decline in monoamines (NE, DA, 5-HT) induced by PSD (allP<0.05).Conclusion Rice bran oil rich in oryzanol may alleviate fatigue and improve sleep in mice with PSD through modulation of monoamines (NE, DA, 5-HT).