Neurogenetics of food anticipation.
Circadian clocks enable the organisms to anticipate predictable cycling events in the environment. The mechanisms of the main circadian clock, localized in the suprachiasmatic nuclei of the hypothalamus, involve intracellular autoregulatory transcriptional loops of specific genes, called clock genes. In the suprachiasmatic clock, circadian oscillations of clock genes are primarily reset by light, thus allowing the organisms to be in phase with the light-dark cycle. Another circadian timing system is dedicated to preparing the organisms for the ongoing meal or food availability: the so-called food-entrainable system, characterized by food-anticipatory processes depending on a circadian clock whose location in the brain is not yet identified with certainty. Here we review the current knowledge on food anticipation in mice lacking clock genes or feeding-related genes. The food-entrainable clockwork in the brain is currently thought to be made of transcriptional loops partly divergent from those described in the light-entrainable suprachiasmatic nuclei. Possible confounding effects associated with behavioral screening of meal anticipation in mutant mice are also discussed.
Centre National de la Recherche Scientifique, UPR3212 associé à l'Université de Strasbourg, Institut de Neurosciences Cellulaires et Intégratives, Département de Neurobiologie des Rythmes, 5 rue Blaise Pascal, 67084 Strasbourg, France. challet@inci-cnrs.unistra.fr
Etienne
E
Challet
Jorge
J
Mendoza
Hugues
H
Dardente
Paul
P
Pévet
D000818:Animals; D001522:Behavior, Animal / Q000502:physiology; D001683:Biological Clocks / Q000235:genetics* / Q000502:physiology; D002940:Circadian Rhythm / Q000235:genetics* / Q000502:physiology; D056925:Circadian Rhythm Signaling Peptides and Proteins / Q000235:genetics / Q000378:metabolism; D005215:Fasting; D005247:Feeding Behavior / Q000502:physiology*; D005786:Gene Expression Regulation; D006706:Homeostasis; D008027:Light; D017440:Photoperiod; D013493:Suprachiasmatic Nucleus / Q000378:metabolism; D013997:Time Factors
D056925:Circadian Rhythm Signaling Peptides and Proteins