Abstract
Feeding and drinking rhythms were studied in rats maintained under 24-hr light-dark (LD) cycles with various photoperiods, under two-pulse (2P) and one-pulse (1P) skeleton photoperiods, and under constant dark (DD). Rhythmic waveforms were similar under complete LD cycles and corresponding skeleton photoperiods, indicating that these rhythms mainly reflect the entrainment of underlying circadian pacemakers. Little or no role was found for masking effects of light on circadian feeding and drinking waveforms. Entrainment was found to depend mainly on the timing of the dawn light signal, whether it was a 15-min light pulse or a dark-to-light transition initiating a complete photoperiod. Furthermore, the use of 1P schedules revealed that a dawn signal was sufficient for entrainment. These results closely match those obtained for motor activity measures in other nocturnal rodent species, and generally conform to the predictions of Pittendrigh's nonparametric theory of entrainment. Furthermore, the close correspondence of the two rhythms during entrainment, phase-jumps, and free-running (DD) conditions indicates that they are controlled by common circadian pacemakers.
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
