Intracerebroventricular injection of orexins does not stimulate food intake in neonatal chicks.
1. Recently, 2 novel neuropeptides were discovered, both derived from the same precursor by proteolytic processing, which bind and activate 2 closely related orphan G protein-coupled receptors, Named orexin-A and -B (Sakurai et al., 1998). Both stimulate food intake when administered centrally to rats. 2. Our aim was to elucidate whether central injection of mammalian orexin-A or -B stimulates food intake in the chick. 3. Under conditions of free access to food, orexin-A did not alter the food intake of chicks, but cumulative food intake was significantly suppressed by orexin-B. 4. The orexin-B was then administered to chicks deprived of food for 3 h to confirm its suppressive effect. No significant effect of orexin-B on food intake was detected. 5. Central injection of orexin-B did not modify food intake when appetite was stimulated by fasting. 6. Neither of these orexins appears to stimulate feeding in chicks.
Furuse
M
M
Laboratory of Animal Feed Science, Faculty of Agriculture, Kyushu University, Fukuoka, Japan. furuse@agr.kyushu-u.ac.jp
Ando
R
R
Bungo
T
T
Ao
R
R
Shimojo
M
M
Masuda
Y
Y
D000818:Animals; D000831:Animals, Newborn; D002352:Carrier Proteins / Q000008:administration & dosage / Q000494:pharmacology*; D002417:Cattle; D002645:Chickens / Q000378:metabolism*; D002149:Energy Intake / Q000187:drug effects*; D007276:Injections, Intraventricular; D047908:Intracellular Signaling Peptides and Proteins; D008297:Male; D051379:Mice; D009479:Neuropeptides / Q000008:administration & dosage / Q000494:pharmacology*; D000068797:Orexins; D051381:Rats
D002352:Carrier Proteins; D047908:Intracellular Signaling Peptides and Proteins; D009479:Neuropeptides; D000068797:Orexins