REM sleep disorder has a significant deleterious impact on postoperative outcome. EEG microstructure during distinct stable anesthetized states is different. Distinct general anesthesia regimens prolonged the post-anesthesia REM sleep in rat. Prolonged REM without atonia was demonstrated only after ketamine/diazepam anesthesia. Pentobarbital anesthesia is beneficial for the post-anesthesia REM sleep in rat.