Effects of single and chronic intracerebroventricular administration of the orexins on feeding in the rat.
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.
Haynes
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AC
Vascular Biology, SmithKline Beecham Pharmaceuticals, Harlow, Essex, UK. AndreaHaynesl@sbpgrd.com
Jackson
B
B
Overend
P
P
Buckingham
R E
RE
Wilson
S
S
Tadayyon
M
M
Arch
J R
JR
D000818:Animals; D002352:Carrier Proteins / Q000008:administration & dosage* / Q000494:pharmacology; D005247:Feeding Behavior / Q000187:drug effects*; D007275:Injections, Intravenous; D007276:Injections, Intraventricular; D047908:Intracellular Signaling Peptides and Proteins; D008297:Male; D009479:Neuropeptides / Q000008:administration & dosage* / Q000494:pharmacology; D000068797:Orexins; D017440:Photoperiod; D051381:Rats; D017207:Rats, Sprague-Dawley; D017208:Rats, Wistar
D002352:Carrier Proteins; D047908:Intracellular Signaling Peptides and Proteins; D009479:Neuropeptides; D000068797:Orexins