ABSTRACT
Fumonisin B1 (FB1) structurally resembles sphingolipids and interferes with their metabolism leading to sphingolipid dysregulation. We questioned if FB1 could exacerbate liver or kidney toxicities in glutathione peroxidase 1 (Gpx1) and catalase (Cat) knockout mice. While higher serum levels of thiobarbituric acid reactive substances (TBARS) and sphinganine (Sa) were measured in Gpx1/Cat knockout mice (Gpx1/Cat KO) than wild type mice after 5 days of FB1 treatment, serum levels of alanine aminotransferase (ALT), sphingosine-1 phosphate (So-1-P), and sphinganine-1 phosphate (Sa-1-P) were found to be relatively low. Although Sa was highly elevated in Gpx1/Cat KO mice and wild mice, lower levels of So and Sa were found in both the kidney and liver tissues of Gpx/Cat KO mice than wild type mice after FB1 treatment. Paradoxically, FB1-induced cellular apoptosis and necrosis were hastened under oxidative stress in Gpx1/Cat KO mice.
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 α(S1)-casein (α(S1)-CH) has been shown to possess stress relieving and sleep promoting effects. However, the differential effects of α(S1)-CH on electroencephalographic wave patterns and its effects on the protein levels of γ-aminobutyric acid A (GABA(A)) receptor subtypes in hypothalamic neurons are not well understood. We found α(S1)-CH (120, 240 mg/kg) increased sleep duration in mice and reduced sleep-wake cycle numbers in rats. While α(S1)-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 α(S1)-CH (300 mg/kg) during sleep-wake cycles. Furthermore, protein expressions of GABA(A) receptor β1 subtypes were elevated in rat hypothalamus by α(S1)-CH. These results suggest α(S1)-CH, through GABA(A) receptor modulation, might be useful for treating sleep disorders.