To a Problem of Anabolic Function of Sleep

Proceedings of the 9th International Multidisciplinary Conference «Stress and Behavior» Saint-Petersburg, Russia, 16–19 May 2005.Many different functions of sleep are currently known. One of them is anabolic function, including the recovery of processes disturbed in the condition of wakefulness, and accumulation of the definite energetic and/or plastic potential for the subsequent wakefulness. N.A. Rozhansky called this function «a renewing sense of sleep». However sleep is not a homogeneous process. It is therefore of interest, with what phase or stage of sleep, and how, its anabolic function is linked. One of experimental approaches to this may be a fast transition of an organism to catabolism. Therefore, it is necessary to assess parallel recovery of the process in the CNS and dynamics of wakefulness-sleep cycle. As the activity of the CNS relates to free radical processes, it is logical to study the influence on sleep and its recovering processes of a new antioxidant synthesized at the Institute of the Physic-Organic Chemistry of Rostov University, — dimethyldipyrazolelselenid (DMDPS).Methods. Electrodes for the polygraphic recording were preliminary implanted in the chinchilla rabbits (2–2.5 years, 4–5 kg) under a local anesthesia with 0.5 % Novocain, to record electrocorticogram (EEG) of the symmetrical points of frontal and occipital areas of the cortex, electromyogram (EMG) of cervical muscles, electrooculogram (EOG) of both eyes, and electrocardiogram (ECG). Using special sensors, we measured the respiration intensity, body temperature, and saturation of the arterial blood by oxygen (SaO2). The polygrams were recorded and analyzed by computer polygraph «Lab of sleep» (SAGURA Medizintechnik GmbH, Germany). The blood for biotechnical analyses was taken from aural and bulbar veins. The change of the functional condition of the organism — hypoxia hypoxic was invoked by the increase of respiratory paths by a handset. The isoosmotic solution DMDPS was injected i.p.Results and discussion. The animals subjected to the hypoxia, initially (for several hours) showed increased general duration of sleep (from 32 to 43 %), also reducing the periods of the wakefulness. The increase of the duration of sleep was mostly due to the slow wave sleeping phase (from 31 % in control to 41.5 %). The paradoxical sleep increased only slightly, from 0.7–1.0 % to 2 %. These changes in sleep on Day 1 preserved on Day 2–3, returning to the initial levels by Day 7–10. The slow wave sleep was permanently restored; the general duration of the paradoxical sleep during the 1st days remained on a high level and only reduced much later. The similar results were obtained by the colleagues in the experiments with Wister rats, with the occlusion of carotid arteries. The introduction of DMDPS immediately after the hypoxia did not influence the character of the subsequent dynamics of parameters of the wakefulness–sleep cycle, but accelerated their recovery.Conclusion. Hypoxia activates recovering functions of the brain, including increased general duration of sleep and its phases. The different character of the changes of the slow wave and paradoxical sleep phases indicates that the anabolic function of sleep can be realized in its different phases. A. Kogan et al. showed that the mechanisms for such recovering processes may not be simple. On one hand, there are data which allow us to assume that the paradoxical sleep promotes brain synthesis. On the other hand it is known that the slow wave sleep also participates in the recovering processes, in particular, in the decrease of the intensity of free radical processes. The latter is confirmed by our data studying the influence of DMDPS on sleep. Research was supported by the grant RFBRI 04–04-96806-p2004-south.