The role of cholecystokinin octapeptide in the central control of food intake in the dog.
Cholecystokinin octapeptide (CCK-8, 1, 190 pmol/5 min) decreased food intake and water consumption in two models of ingestive behavior, i.e., food deprivation-induced feeding and insulin-induced feeding, when administered into the third (3V) and lateral (LV) cerebral ventricles. In fasted dogs, the suppression of food intake was more prominent after 3V CCK-8, whereas intravenously administered CCK-8 was without effect. Neuropeptide Y (NPY, 1, 190 pmol) had no significant stimulatory effect on food intake and water consumption in fasted as well as satiated dogs, and actually reduced both food and water intake in insulin-treated dogs. There was a slight but significant decrease in food and water intake after 275 nmol naloxone administration in both feeding models, and some of the dogs vomited. In insulin-treated animals, CCK-8 reversed, but NPY potentiated the hypothermic phase of temperature response observed after saline administration, whereas naloxone failed to alter rectal temperature. These results suggest that the effect of CCK-8 on feeding seems to involve central mechanisms in the dog, and that the mechanisms by which CCK-8, NPY and naloxone affect feeding behavior are different.
Sakatani
N
N
Inui
A
A
Inoue
T
T
Oya
M
M
Morioka
H
H
Baba
S
S
D000818:Animals; D002552:Cerebral Ventricles / Q000187:drug effects / Q000502:physiology*; D004285:Dogs; D004327:Drinking Behavior / Q000187:drug effects*; D005215:Fasting; D005247:Feeding Behavior / Q000187:drug effects*; D005508:Food Deprivation; D007276:Injections, Intraventricular; D007328:Insulin / Q000494:pharmacology; D009270:Naloxone / Q000494:pharmacology; D009478:Neuropeptide Y / Q000494:pharmacology; D012844:Sincalide / Q000008:administration & dosage / Q000494:pharmacology*
D007328:Insulin; D009478:Neuropeptide Y; D009270:Naloxone; D012844:Sincalide