Effects of single and chronic intracerebroventricular administration of the orexins on feeding in the rat

Peptides. 1999;20(9):1099-105. doi: 10.1016/s0196-9781(99)00105-9.


Two novel hypothalamic neuropeptides, orexin-A and -B, are suggested to regulate feeding. A single intracerebroventricular injection of orexin-A (23.4 nmol), administered 3 h into the light phase, increased feeding in satiated rats and prolonged feeding in fasted rats; it also increased feeding when given 6 h into, but not at the start of, the dark phase. An 8-day intracerebroventricular infusion with orexin-A (18 nmol/day) increased daytime feeding on days 2 and 8, but nocturnal feeding was reduced and there was no change in 24 h intake. Orexin-B had no effects. These results demonstrate a circadian variation in feeding responses to orexin-A.

MeSH terms

  • Animals
  • Carrier Proteins / administration & dosage*
  • Carrier Proteins / pharmacology
  • Feeding Behavior / drug effects*
  • Injections, Intravenous
  • Injections, Intraventricular
  • Intracellular Signaling Peptides and Proteins*
  • Male
  • Neuropeptides / administration & dosage*
  • Neuropeptides / pharmacology
  • Orexins
  • Photoperiod
  • Rats
  • Rats, Sprague-Dawley
  • Rats, Wistar


  • Carrier Proteins
  • Intracellular Signaling Peptides and Proteins
  • Neuropeptides
  • Orexins