The Effect of Rice Flour for Amelioration of Sleeping in Social Isolated Mice

Abstract

In an era where the health-damaging effects of wheat flour (gluten) are increasingly recognized, rice flour has become an important alternative for many people, yet its psychophysiological effects remain largely unknown. Here, we report the potential beneficial effects of rice flour for sleep disturbances in stressed mice. Four-week-old male ddY mice were reared in social isolation for 4 weeks. The control group was reared in a social group. Rice flour was given orally in food to isolated mice at a dose of 2.5 w/w% and 5.0 w/w% for 4 weeks from the start of isolation rearing. MF food was given to the control group. Pentobarbital-induced (40 mg/kg, i.p.) time to sleep induction and righting reflex was measured to determine the effects of rice flour on sleep behavior. Blood samples were obtained after the experiments, and serum corticosterone was measured. Sections from the prefrontal cortex and the brainstem were isolated to measure serotonin, dopamine and interleukin (IL)-6 concentrations. We found that the administration of rice flour dose-dependently improved time to sleep and reduced sleep time in socially isolated mice. Blood corticosterone concentrations, which increased after isolation stress, were decreased after the administration of rice flour. Serotonin and dopamine concentrations in the prefrontal cortex which decreased after isolation stress improved after the administration of rice flour. Brainstem IL-6 concentrations increased after isolation stress, but decreased dose-dependently after rice flour administration. Our results suggest that rice flour reverses sleep disturbances in mice induced by social isolation.