Hypoxia-induced sleep disturbance in rats

The effects of varying degrees of hypoxia on sleep-wake organization were studied in rats prepared for chronic electrophysiological recording. The influence of Piracetam (75, 50, and 500 mg/kg, i.p.) and Hydergine (0.5, 1, and 3 mg/kg, i.p.) on sleep-wake organization in 10.5% oxygen was also investigated. The sleep-wake organization of rats under the effect of 15.5% oxygen content was unchanged, compared to that of normoxic control. More extreme hypoxia (12.6 and 10.5% oxygen) produced dramatic changes in sleep organization without influencing gross behavior. Paradoxical sleep (PS) stages became less frequent and shortened and were totally absent in 10.5% oxygen. Frequent wakings caused disturbed and superficial sleep. Central biochemical mechanisms, peripheral chemoreceptor reflex pathways and, as a consequence, decrease of duration of deep sleep periods, may contribute to the development of hypoxic sleep disturbances. Piracetam alleviated and Hydergine moderately reversed the hypoxic sleep disturbance.