Entrainment of temperature and activity rhythms to restricted feeding in orexin knock out mice

Satvinder Kaur, Stephen Thankachan, Suraiya Begum, Carlos Blanco-Centurion, Takeshi Sakurai, Masashi Yanagisawa, Priyattam J. Shiromani

Research output: Contribution to journalArticlepeer-review

55 Scopus citations


Ablation of the SCN, an established circadian clock, does not abolish food entrainment, suggesting that the food-entrainable oscillator (FEO) must lie outside the SCN. Typically, animals show anticipatory locomotor activity and rise in core body temperature under the influence of the FEO. Signals from the FEO would, therefore, converge onto arousal neurons so that the animal might forage for food. In the present study, we investigate whether the neuropeptide orexin, which has been linked to arousal, might transduce the arousal signal. Orexin-knockout (orexin-KO) and wildtype (WT) mice (both C57BL/6J derived) were implanted with MiniMitter transmitters that recorded core body temperature and activity (12 h LD cycle). After a week of ad-libitum feeding, the mice were given access to food for 4 h (ZT 4-8) for nine days followed by 2-days of fasting. When orexin-KO mice were placed in a restricted feeding schedule, both core body temperature and activity entrained to the feeding schedule. In these mice gross locomotor activity was severely blunted during the nine day period of restricted feeding (- 79.4 ± 6.3%) from the WT, but they showed an increase in core body temperature in anticipation to the meal time similar to the WT mice. There was no difference in the amount of food intake between the genotypes. We conclude that orexin is not required for entrainment of activity and temperature to a restricted feeding schedule, but is required for the robust expression of gross locomotor activity in anticipation of the scheduled feeding.

Original languageEnglish (US)
Pages (from-to)47-54
Number of pages8
JournalBrain Research
StatePublished - Apr 18 2008


  • Activity
  • Core body temperature
  • Food anticipatory rhythms
  • Orexin
  • Restricted feeding
  • Transgenic mice

ASJC Scopus subject areas

  • Neuroscience(all)
  • Molecular Biology
  • Clinical Neurology
  • Developmental Biology


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