Abstract: (1)Theoretical approaches to sleep: Despite the fact that nearly one-third of our life is spent in sleep, theexplanation of our need for sleep remains elusive. Ancient and contemporarytheories concerning the function of sleep have been discussed. (2)"Dry" mechanisms of sleep: A great deal of impetus was given to sleep by the development of EBG,EOG and EMG recording techniques. It is generally accepted that there arefour different stages of non-REM sleep in adults. Our results show that itseems to have only three stages of non-REM, sleep for children aged 3-7years. Tentative theories concerning the significance of REM sleep have beensuggested. (3)"Wet" mechanisms of sleep: Sleep is correlated with hypothalamic-pituitary neuroendocrines, biogenicamines and specific sleep-inducing substances. We demonstrate the delta andsigma EEG-enhancing effects of pure α-aspartyl DSIP synthesized by uswith the liquid-phase method. We also demonstrate the delta and sigma EEG-enhancing effects of a new substance synthesized by us with the solid-phasemethod. It is a nonapeptide with the amino-acid sequence Trp-Ala-Gly-Gly-Phe-Ala-Ser-Gly-Glu.

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