title: Food-anticipatory activity in Syrian hamsters: behavioral and molecular responses in the hypothalamus according to photoperiodic conditions.
abstract: When food availability is restricted, animals adjust their behavior according to the timing of food access. Most rodents, such as rats and mice, and a wide number of other animals express before timed food access a bout of activity, defined as food-anticipatory activity (FAA). One notable exception amongst rodents is the Syrian hamster, a photoperiodic species that is not prone to express FAA. The present study was designed to understand the reasons for the low FAA in that species. First, we used both wheel-running activity and general cage activity to assess locomotor behavior. Second, the possible effects of photoperiod was tested by challenging hamsters with restricted feeding under long (LP) or short (SP) photoperiods. Third, because daytime light may inhibit voluntary activity, hamsters were also exposed to successive steps of full and skeleton photoperiods (two 1-h light pulses simulating dawn and dusk). When hamsters were exposed to skeleton photoperiods, not full photoperiod, they expressed FAA in the wheel independently of daylength, indicating that FAA in the wheel is masked by daytime light under full photoperiods. During FAA under skeleton photoperiods, c-Fos expression was increased in the arcuate nuclei independently of the photoperiod, but differentially increased in the ventromedial and dorsomedial hypothalamic nuclei according to the photoperiod. FAA in general activity was hardly modulated by daytime light, but was reduced under SP. Together, these findings show that food-restricted Syrian hamsters are not prone to display FAA under common laboratory conditions, because of the presence of light during daytime that suppresses FAA expression in the wheel.
authors.affiliation: Department of Neurobiology of Rhythms, Institute of Cellular and Integrative Neurosciences, UPR 3212 CNRS, University of Strasbourg, Strasbourg, France; Department of Physiology and Biophysics, Institute of Biomedical Sciences, University of São Paulo, São Paulo, Brazil.
authors.forename: Rosana F
authors.initials: RF
authors.lastname: Dantas-Ferreira
authors.affiliation: Department of Neurobiology of Rhythms, Institute of Cellular and Integrative Neurosciences, UPR 3212 CNRS, University of Strasbourg, Strasbourg, France.
authors.forename: Stéphanie
authors.initials: S
authors.lastname: Dumont
authors.affiliation: Department of Neurobiology of Rhythms, Institute of Cellular and Integrative Neurosciences, UPR 3212 CNRS, University of Strasbourg, Strasbourg, France.
authors.forename: Sylviane
authors.initials: S
authors.lastname: Gourmelen
authors.affiliation: Department of Physiology and Biophysics, Institute of Biomedical Sciences, University of São Paulo, São Paulo, Brazil.
authors.forename: José
authors.initials: J
authors.lastname: Cipolla-Neto
authors.affiliation: Department of Neurobiology of Rhythms, Institute of Cellular and Integrative Neurosciences, UPR 3212 CNRS, University of Strasbourg, Strasbourg, France.
authors.forename: Valérie
authors.initials: V
authors.lastname: Simonneaux
authors.affiliation: Department of Neurobiology of Rhythms, Institute of Cellular and Integrative Neurosciences, UPR 3212 CNRS, University of Strasbourg, Strasbourg, France.
authors.forename: Paul
authors.initials: P
authors.lastname: Pévet
authors.affiliation: Department of Neurobiology of Rhythms, Institute of Cellular and Integrative Neurosciences, UPR 3212 CNRS, University of Strasbourg, Strasbourg, France.
authors.forename: Etienne
authors.initials: E
authors.lastname: Challet
mesh_terms: D000818:Animals; D006224:Cricetinae; D005247:Feeding Behavior; D006854:Hydrocortisone / Q000097:blood; D007031:Hypothalamus / Q000378:metabolism*; D008647:Mesocricetus; D017440:Photoperiod; D016760:Proto-Oncogene Proteins c-fos / Q000378:metabolism
chemical_list: D016760:Proto-Oncogene Proteins c-fos; D006854:Hydrocortisone