title: Behavioural food anticipation in clock genes deficient mice: confirming old phenotypes, describing new phenotypes.
abstract: Animals fed daily at the same time exhibit circadian food-anticipatory activity (FAA), which has been suggested to be driven by one or several food-entrainable oscillators (FEOs). FAA is altered in mice lacking some circadian genes essential for timekeeping in the main suprachiasmatic clock (SCN). Here, we confirmed that single mutations of clock genes Per1(-/-) and Per2(Brdm1) alter FAA expression in constant darkness (DD) or under a light-dark cycle (LD). Furthermore, we found that Per1(-/-);Per2(Brdm1) and Per2(Brdm1);Cry1(-/-) double mutant animals did not display a stable and significant FAA either in DD or LD. Interestingly, rescued behavioural rhythms in Per2(Brdm1);Cry2(-/-) mice in DD were totally entrained to feeding time and re-synchronized after phase-shifts of mealtime, indicating a higher SCN sensitivity to feeding cues. However, under an LD cycle and restricted feeding at midday, FAA in double Per2(Brdm1);Cry2(-/-) mutant mice was absent. These results indicate that shutting down one or two clock genes results in altered circadian meal anticipation. Moreover, we show that in a genetically rescued SCN clock (Per2(Brdm1);Cry2(-/-)), food is a powerful zeitgeber to entrain behavioural rhythms, leading the SCN to be more sensitive to feeding cues than in wild-type littermates.
authors.affiliation: Institut de Neurosciences Cellulaires et Intégratives, Département de Neurobiologie des Rythmes, Centre National de la Recherche Scientifique, UPR3212 associée à l'Université de Strasbourg, France. jmendoza@inci-cnrs.unistra.fr
authors.forename: J
authors.initials: J
authors.lastname: Mendoza
authors.forename: U
authors.initials: U
authors.lastname: Albrecht
authors.forename: E
authors.initials: E
authors.lastname: Challet
mesh_terms: D000704:Analysis of Variance; D000818:Animals; D001070:Appetitive Behavior / Q000502:physiology; D001245:Association Learning; D001522:Behavior, Animal / Q000502:physiology; D002940:Circadian Rhythm / Q000235:genetics*; D056931:Cryptochromes / Q000235:genetics* / Q000378:metabolism; D005247:Feeding Behavior; D005260:Female; D051379:Mice; D018345:Mice, Knockout; D008818:Mice, Neurologic Mutants; D056950:Period Circadian Proteins / Q000235:genetics* / Q000378:metabolism; D017440:Photoperiod; D018709:Statistics, Nonparametric; D013493:Suprachiasmatic Nucleus / Q000378:metabolism*
chemical_list: C538964:Cry1 protein, mouse; C538967:Cry2 protein, mouse; D056931:Cryptochromes; C539023:Per1 protein, mouse; C513312:Per2 protein, mouse; D056950:Period Circadian Proteins