Abstract
Phaseshifting effects of timed calorie restriction were investigated in mice during exposure to a 12:12-h light-dark cycle. Food-anticipatory activity (FAA), the output of a food-entrainable pacemaker, was expressed before the time of feeding whether mice received daily hypocaloric food (3.3 g of chow/day) or normocaloric food (5 g of chow/day) at zeitgeber time (ZT) 2 (ZT12 = lights off). Subsequently, mice were placed in constant darkness and fed ad libitum. The onset of the nocturnal period of locomotor activity was phase advanced by I h in calorie-restricted mice compared with normocalorie-fed controls. The phase advance still occurred when FAA was prevented by restraining calorie-restricted mice. Giving hypocaloric food at ZT2, ZT10, ZT14, or ZT22 phase advanced the nocturnal pattern of activity by 1, 3, 1, and 1 h, respectively. After transfer to constant darkness, FAA free ran in parallel with the normal nocturnal period of locomotor activity. A light pulse during the early subjective night phase delayed both components. These results indicate that 1) timed calorie restriction under a light-dark cycle can phase advance the light-entrainable pacemaker with a phase- dependent magnitude, 2) FAA feedback is not crucial for the observed phase advance, and 3) the light-entrainable pacemaker may control the period of the food-entrainable pacemaker in mice fed ad libitum.
Original language | English (US) |
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Pages (from-to) | R1751-R1761 |
Journal | American Journal of Physiology - Regulatory Integrative and Comparative Physiology |
Volume | 274 |
Issue number | 6 43-6 |
DOIs | |
State | Published - 1998 |
Keywords
- Circadian rhythm
- Food synchronization
- Food-anticipatory activity
- Suprachiasmatic nucleus
ASJC Scopus subject areas
- Physiology
- Physiology (medical)