Cinnamaldehyde Antagonizes REM Sleep Reduction Induced by Immobilization Stress in Rats

Background and purpose: Sleep and stress are linked in a bidirectional manner. Immobilization stress is a simple model that could be used easily in animal studies for understanding the neurobiology of stress-sleep relationship. Cinnamaldehyde as a herbal medicine with antioxidant activities could be investigated in modulating sleep-stress interaction. Materials and methods: In the present study, we examined the effects of immobilization stress combined with physical stress on sleep stages in male Wistar rats. Sleep stages were evaluated through EEG and EMG signals before and after stress induction during three consecutive days. The rats received Cinnamaldehyde orally by gavage at the dose level of 20 mg/kg/day. The treatment was started one week before surgery and lasted for 18 days. Results: Findings showed that immobilization stress decreased the rapid eye movement (REM) sleep (P= 0.01). In the stress exposed group treated with Cinnamaldehyde not only there were no decrease in REM sleep but also there were increase in REM and non-rapid eye movement (NREM) sleep. Conclusion: Cinnamaldehyde could improve sleep and repair REM sleep disturbance induced by stress.