Premium
Unpredictable feeding schedules unmask a system for daily resetting of behavioural and metabolic food entrainment
Author(s) -
Escobar Carolina,
MartínezMerlos Ma Teresa,
AngelesCastellanos Manuel,
Del Carmen Miñana María,
Buijs Ruud M.
Publication year - 2007
Publication title -
european journal of neuroscience
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.346
H-Index - 206
eISSN - 1460-9568
pISSN - 0953-816X
DOI - 10.1111/j.1460-9568.2007.05893.x
Subject(s) - zeitgeber , suprachiasmatic nucleus , meal , entrainment (biomusicology) , hypophagia , medicine , endocrinology , biology , circadian rhythm , food intake , rhythm , circadian clock
Restricted feeding schedules (RFS) are a potent Zeitgeber that uncouples daily metabolic and clock gene oscillations in peripheral tissues from the suprachiasmatic nucleus (SCN), which remains entrained to the light–dark cycle. Under RFS, animals develop food anticipatory activity (FAA), characterized by arousal and increased locomotion. Food availability in nature is not precise, which suggests that animals need to adjust their food‐associated activity on a daily basis. This study explored the capacity of rats to adjust to variable and unpredictable feeding schedules. Rats were exposed either to RFS with fixed daily meal (RF) or to a variable meal time (VAR) during the light phase. RF and VAR rats exhibited daily metabolic oscillations driven by the last meal event; however, VAR rats were not able to show a robust adjustment in the anticipating corticosterone peak. VAR rats were unable to exhibit FAA but exhibited a daily activation pattern in phase with the previous meal. In both groups the dorsomedial nucleus of the hypothalamus and arcuate nucleus, involved in energy balance, exhibited increased c‐Fos expression 24 h after the last meal, while only RF rats exhibited low c‐Fos expression in the SCN. Data show that metabolic and behavioural food‐entrained rhythms can be reset on a daily basis; the two conditions elicit a similar hypothalamic response, while only the SCN is inhibited in rats exhibiting anticipatory activity. The variable feeding strategy uncovered a rapid (24‐h basis) resetting mechanism for metabolism and general behaviour.