Feeding and activity induced by orexin A in the lateral hypothalamus in rats

Catherine M. Kotz, Jennifer A. Teske, James A. Levine, Chuan Feng Wang

Research output: Contribution to journalArticlepeer-review

137 Scopus citations


Orexin A injected into the lateral hypothalamus (LH) stimulates feeding and activates neurons in brain sites regulating feeding and arousal. The feeding effects of orexin A have been demonstrated during the light cycle, a time when rats are normally resting, and the effect of orexin A on activity after injection into the LH has not been previously measured. Thus, it is unclear whether LH orexin A-induced feeding is secondary to enhanced arousal. To address this, LH-cannulated rats habituated to a running wheel were injected with either orexin A (1000 pmol) or vehicle during light and dark cycles. Food intake and running wheel rotations were measured for 2 h. Spontaneous physical activity (SPA) was also measured during the dark cycle. During the light cycle, orexin A in the LH stimulated feeding in the presence and absence of a running wheel and increased number of running wheel rotations in the presence and absence of food. During the dark cycle, orexin A in the LH induced SPA (±presence of food), but had no effect on feeding. These data show that LH orexin A stimulation of feeding is not always coincident with increased activity, suggesting that feeding induced by LH-injected orexin A is not consequent to enhanced arousal. Published by Elsevier Science B.V.

Original languageEnglish (US)
Pages (from-to)27-32
Number of pages6
JournalRegulatory Peptides
Issue number1-3
StatePublished - Mar 15 2002


  • Arousal
  • Feeding behavior
  • Hypocretin 1
  • Lateral hypothalamus
  • Orexin A
  • Sleep

ASJC Scopus subject areas

  • Biochemistry
  • Physiology
  • Endocrinology
  • Clinical Biochemistry
  • Cellular and Molecular Neuroscience


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