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is the food-entrainable circadian oscillator in the digestive system?Food-anticipatory activity (FAA) is the increase in locomotion and core body temperature that precedes a daily scheduled meal. It is driven by a circadian oscillator but is independent of the suprachiasmatic nuclei. Recent results that reveal meal-entrained clock gene expression in rat and mouse peripheral organs raise the intriguing possibility that the digestive system is the site of the feeding-entrained oscillator (FEO) that underlies FAA. We tested this possibility by comparing FAA and Per1 rhythmicity in the digestive system of the Per1-luciferase transgenic rat. First, rats were entrained to daytime restricted feeding (RF, 10 days), then fed ad libitum (AL, 10 days), then food deprived (FD, 2 days). As expected FAA was evident during RF and disappeared during subsequent AL feeding, but returned at the correct phase during deprivation. The phase of Per1 in liver, stomach and colon shifted from a nocturnal to a diurnal peak during RF, but shifted back to nocturnal phase during the subsequent AL and remained nocturnal during food deprivation periods. Second, rats were entrained to two daily meals at zeitgeber time (ZT) 0400 and ZT 1600. FAA to both meals emerged after about 10days of dual RF. However, all tissues studied (all five liver lobes, esophagus, antral stomach, body of stomach, colon) showed entrainment consistent with only the night-time meal. These two results are inconsistent with the hypothesis that FAA arises as an output of rhythms in the gastrointestinal (GI) system. The results also highlight an interesting diversity among peripheral oscillators in their ability to entrain to meals and the direction of the phase shift after RF ends.
Document ID
20040087581
Document Type
Reprint (Version printed in journal)
Authors
Davidson, A. J.
(University of Virginia Charlottesville, Virginia 22904, United States)
Poole, A. S.
Yamazaki, S.
Menaker, M.
Date Acquired
August 21, 2013
Publication Date
February 1, 2003
Publication Information
Publication: Genes, brain, and behavior
Volume: 2
Issue: 1
ISSN: 1601-1848
Subject Category
Life Sciences (General)
Funding Number(s)
CONTRACT_GRANT: MH 56647
CONTRACT_GRANT: T32-DK07646-10
Distribution Limits
Public
Copyright
Other
Keywords
Non-NASA Center
NASA Discipline Space Human Factors