Administration of alphas1-casein hydrolysate increases sleep and modulates GABAA receptor subunit expression

Abstract

Sleep is the most basic and essential physiological requirement for mental health, and sleep disorders pose potential risks of metabolic and neurodegenerative diseases. Tryptic hydrolysate of αS1 -casein (αS1 -CH) has been shown to possess stress relieving and sleep promoting effects. However, the differential effects of αS1 -CH on electroencephalographic wave patterns and its effects on the protein levels of γ-aminobutyric acid A (GABAA) receptor subtypes in hypothalamic neurons are not well understood. We found αS1 -CH (120, 240 mg/kg) increased sleep duration in mice and reduced sleep-wake cycle numbers in rats. While αS1 -CH (300 mg/kg) increased total sleeping time in rats, it significantly decreased wakefulness. In addition, electroencephalographic theta (θ) power densities were increased whereas alpha (α) power densities were decreased by αS1 -CH (300 mg/kg) during sleep-wake cycles. Furthermore, protein expressions of GABAA receptor β1 subtypes were elevated in rat hypothalamus by αS1 -CH. These results suggest αS1 -CH, through GABAA receptor modulation, might be useful for treating sleep disorders. © 2018 The Korean Society of Applied Pharmacology.