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- Title
Is the food-entrainable circadian oscillator in the digestive system?
- Authors
Davidson, A. J.; Poole, A. S.; Yamazaki, S.; Menaker, M.
- Abstract
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 gone 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, 10days), then fed ad libitum AL, 10 days), then food deprived FD, 2days). 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 10 days 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.
- Subjects
LOCOMOTION; CIRCADIAN rhythms; NUCLEAR physics; GASTROINTESTINAL system; SUPRACHIASMATIC nucleus
- Publication
Genes, Brain & Behavior, 2003, Vol 2, Issue 1, p32
- ISSN
1601-1848
- Publication type
Article
- DOI
10.1034/j.1601-183X.2003.00005.x