|Neurobiology of Rhythms|
|Team "Circadian clocks & metabolism"|
Interactions between brain clocks and feeding: temporal and energetic aspects
The ability to predict and anticipate mealtime is likely a key for survival in most animals. In response to daily limited access to food, animals express food-anticipatory activity. This behavior is considered to be the output of a network of food-entrainable cerebral clocks, called the "food clock". Our pioneering work has revealed that the cerebellum contains a self-sustained clock belonging to the circadian network of the food clock, also involving the metabolic hypothalamus and brainstem. Regarding molecular mechanisms of the food clock, we showed an involvement of the circadian gene Period 2 (Per2) in food anticipation (in collaboration with U. Albrecht, Univ. Fribourg, CH). More recently, our work revealed that the circadian gene Rev-erbα is required for the food clock.
We investigate which brain clocks control the daily feeding/fasting cycle and meal anticipation, and what are the chronomodulators linked to meal time that reset the food clock. The oscillating properties of the food-entrainable cerebral network are characterized in organotypic slices using in vitro bioluminescence recording.
Our team has demonstrated that metabolic factors modulate functioning of the master clock located in the suprachiasmatic nuclei of the hypothalamus (SCN). Among others, metabolic cues associated with a hypocaloric diet, independently of feeding time, can modify timing in the suprachiasmatic clock, and increase its circadian responses to light. Conversely, eating a hypercaloric diet slows the suprachiasmatic clock and reduces its circadian responses to light.
To understand the metabolic feedback on suprachiasmatic cells, we assess on the one hand which peripheral signals (metabolic hormones and plasma metabolites) affect the master clock, and also their mechanisms of action in vivo and in vitro.
in collaboration with Frédéric Doussau (Team 2)
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