title: Entrainment of mouse peripheral circadian clocks to <24 h feeding/fasting cycles under 24 h light/dark conditions.
abstract: The circadian clock system in peripheral tissues can endogenously oscillate and is entrained by the light-dark and fasting-feeding cycles in mammals. Although the system's range of entrainment to light-dark cycles with a non-24 h (<24 h) interval has been studied, the range of entrainment to fasting-feeding cycles with shorter periods (<24 h) has not been investigated in peripheral molecular clocks. In the present study, we measured this range by monitoring the mouse peripheral PER2::LUCIFERASE rhythm in vivo at different periods under each feeding cycle (Tau (T) = 15-24 h) under normal light-dark conditions. Peripheral clocks could be entrained to the feeding cycle with T = 22-24 h, but not to that with T = 15-21 h. Under the feeding cycle with T = 15-18 h, the peripheral clocks oscillated at near the 24-h period, suggesting that they were entrained to the light-dark cycle. Thus, for the first time, we demonstrated the range of entrainment to the non-24 h feeding cycle, and that the circadian range (T = 22-24 h) of feeding stimulus is necessary for peripheral molecular clock entrainment under light-dark cycles.
authors.affiliation: Laboratory of Physiology and Pharmacology, School of Advanced Science and Engineering, Waseda University, Tokyo, Japan.
authors.forename: Yutaro
authors.initials: Y
authors.lastname: Hamaguchi
authors.affiliation: Laboratory of Physiology and Pharmacology, School of Advanced Science and Engineering, Waseda University, Tokyo, Japan.
authors.forename: Yu
authors.initials: Y
authors.lastname: Tahara
authors.affiliation: Laboratory of Physiology and Pharmacology, School of Advanced Science and Engineering, Waseda University, Tokyo, Japan.
authors.forename: Hiroaki
authors.initials: H
authors.lastname: Kuroda
authors.affiliation: Laboratory of Physiology and Pharmacology, School of Advanced Science and Engineering, Waseda University, Tokyo, Japan.
authors.forename: Atsushi
authors.initials: A
authors.lastname: Haraguchi
authors.affiliation: Laboratory of Physiology and Pharmacology, School of Advanced Science and Engineering, Waseda University, Tokyo, Japan.
authors.forename: Shigenobu
authors.initials: S
authors.lastname: Shibata
mesh_terms: D000818:Animals; D057906:Circadian Clocks / Q000502:physiology*; D002940:Circadian Rhythm / Q000502:physiology*; D005215:Fasting / Q000502:physiology; D005247:Feeding Behavior / Q000502:physiology*; D055879:Gene Knock-In Techniques; D051379:Mice; D008810:Mice, Inbred C57BL; D008822:Mice, Transgenic; D017440:Photoperiod