We tested the hypothesis whether daily food availability period would restore rhythmicity in individuals with disrupted circadian behavior with no effect on appetite regulation. Particularly, we investigated the effects of timed food availability on activity behavior, and Fos and neuropeptide Y expressions in Indian weaverbirds (Ploceus philippinus) under atypical light conditions. Initially, weaverbirds in 3 groups of 7–8 each were entrained to 7L:17D (25: < 0.3 lx) with food ad libitum. Thereafter, food availability was restricted for 7 h such that it overlapped with the light period. After a week, 7L:17D was replaced with 3.5L: 3.5D (T7, group 1), 3.5L: 20.5D (T24, group 2) or constant dim light, LLdim (< 0.3 lx, group 3) for 5 weeks. Food cycles synchronized the circadian activity behavior, albeit with group differences, but did not affect body mass, blood glucose levels or testis size. Further, Fos, not NPY mRNA or peptide, expression measured at ZT2 and ZT14 (ZT0 = time of food given) showed significant group differences in the hippocampus, dorsomedial hypothalamus and infundibular nuclear complex. Another identical experiment examined after-effects of the 3 light conditions on persistence of the circadian rhythms. Weaverbirds exposed for 4 weeks to identical food but different light conditions, as above, were released into the free-running condition of food ad libitum and LLdim. Circadian rhythms were decayed in birds previously exposed to T7 LD cycle. Overall, these results show that timed meal restores rhythmicity in individuals with circadian rhythm disruptions without involving neuropeptide Y, the key appetite regulatory molecule.
|Number of pages||9|
|Journal||Physiology and Behavior|
|State||Published - 2016|
Bibliographical noteFunding Information:
DST-IRHPA ( IR/SO/LU-02/2005 ) research funding supported the study.
© 2016 Elsevier Inc.
- Food cycle
- Infundibular nuclear complex
- LD cycle
- Neuropeptide Y
ASJC Scopus subject areas
- Experimental and Cognitive Psychology
- Behavioral Neuroscience