Sleep, brain energy levels, and food intake: Relationship between hypothalamic ATP concentrations, food intake, and body weight during sleep-wake and sleep deprivation in rats.

BACKGROUND

The feeling of hunger and feeding, a wake-state-dependent behavior, is regulated by specific centers within the hypothalamus. While paraventricular nucleus (PVN), arcuate nucleus (ARC), and dorso- and ventromedial hypothalamus (DMH/VMH) regulate feeding, the lateral hypothalamus (LH) is associated both with feeding and wake/REM sleep regulation. In order to examine the effects of sleep and wakefulness on food intake and body weight, we also measured hypothalamic ATP concentrations, which are known to be involved in feeding behavior and sleep-wake regulation.

METHODS

In rats, food intake and body weight was measured during a 24-h light-dark cycle and during 6 h of sleep deprivation (SD) performed by gentle handling. Tissue samples from the PVN, ARC/DMH/VMH, and LH were collected after 6 h of SD and from time-matched diurnal controls. ATP was measured by luciferin-luciferase bioluminescence assay.

RESULTS

Across the 24-h light-dark period, rats consumed approximately 28.13±4.48 g of food and gained 5.22±1.65 g with a positive correlation between food intake and body weight. During SD, while food intake increased significantly +147.31±6.13%, they lost weight significantly (-93.29±13.64%) when compared to undisturbed controls. SD resulted in a significant decrease in ATP levels only in LH (-44.60±21.13%) with no change in PVN, ARC/DMH/VMH region when compared with undisturbed controls.

CONCLUSION

The results indicate a strong overall correlation between ATP concentrations in the LH and individual food intake and suggest a sleep-wake dependent neuronal control of food intake and body weight.