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Cold and hunger induce diurnality in a nocturnal mammal.

ABSTRACT: The mammalian circadian system synchronizes daily timing of activity and rest with the environmental light-dark cycle. Although the underlying molecular oscillatory mechanism is well studied, factors that influence phenotypic plasticity in daily activity patterns (temporal niche switching, chronotype) are presently unknown. Molecular evidence suggests that metabolism may influence the circadian molecular clock, but evidence at the level of the organism is lacking. Here we show that a metabolic challenge by cold and hunger induces diurnality in otherwise nocturnal mice. Lowering ambient temperature changes the phase of circadian light-dark entrainment in mice by increasing daytime and decreasing nighttime activity. This effect is further enhanced by simulated food shortage, which identifies metabolic balance as the underlying common factor influencing circadian organization. Clock gene expression analysis shows that the underlying neuronal mechanism is downstream from or parallel to the main circadian pacemaker (the hypothalamic suprachiasmatic nucleus) and that the behavioral phenotype is accompanied by phase adjustment of peripheral tissues. These findings indicate that nocturnal mammals can display considerable plasticity in circadian organization and may adopt a diurnal phenotype when energetically challenged. Our previously defined circadian thermoenergetics hypothesis proposes that such circadian plasticity, which naturally occurs in nocturnal mammals, reflects adaptive maintenance of energy balance. Quantification of energy expenditure shows that diurnality under natural conditions reduces thermoregulatory costs in small burrowing mammals like mice. Metabolic feedback on circadian organization thus provides functional benefits by reducing energy expenditure. Our findings may help to clarify relationships between sleep-wake patterns and metabolic phenotypes in humans.

SUBMITTER: van der Vinne V

PROVIDER: S-EPMC4210334 | biostudies-literature | 2014 Oct

REPOSITORIES: biostudies-literature

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Cold and hunger induce diurnality in a nocturnal mammal.

van der Vinne Vincent V Riede Sjaak J SJ Gorter Jenke A JA Eijer Willem G WG Sellix Michael T MT Menaker Michael M Daan Serge S Pilorz Violetta V Hut Roelof A RA

Proceedings of the National Academy of Sciences of the United States of America 20141006 42

The mammalian circadian system synchronizes daily timing of activity and rest with the environmental light-dark cycle. Although the underlying molecular oscillatory mechanism is well studied, factors that influence phenotypic plasticity in daily activity patterns (temporal niche switching, chronotype) are presently unknown. Molecular evidence suggests that metabolism may influence the circadian molecular clock, but evidence at the level of the organism is lacking. Here we show that a metabolic c ...[more]

PMID: 25288753

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Cold and hunger induce diurnality in a nocturnal mammal.

Publications

Cold and hunger induce diurnality in a nocturnal mammal.

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