Cholecystokinin interacts with prefeeding to impair runway performance.
Previous experiments demonstrated the ineffectiveness of the C-terminal octapeptide of cholecystokinin (CCK-8) for impairing runway performance by food-deprived rats. These results were consistent with the proposal that CCK-8 does not reduce food intake by inhibiting appetitive motivation but instead acts late in the meal to prematurely trigger satiety. For further evaluation of this hypothesis, the effect of CCK-8 on runway performance was assessed after 21 h food-deprived rats consumed a partial meal of 30% sucrose. Injection of 1.0 micrograms/kg CCK-8 after rats were allowed 3 min (6.2 ml consumed) or 5 min (9.7 ml) access to 30% sucrose produced significant reductions in running speed of 43% and 70%, respectively. After 5 min prefeeding, 0.25 and 0.50 micrograms/kg CCK-8 also produced significant decreases in speed of 20% and 59%, respectively. By contrast, CCK-8 had little or no effect without prefeeding. Doses of 0.25 and 0.50 micrograms/kg failed to affect running speed on these tests and 1.0 micrograms/kg produced a small (7%) though significant decrease. These results suggest that inhibition of feeding motivation after CCK-8 administration develops during the course of the meal through interaction with signals generated by the ingestion of food.
D000818:Animals; D003216:Conditioning, Operant / Q000187:drug effects / Q000502:physiology; D005247:Feeding Behavior / Q000187:drug effects* / Q000502:physiology; D005508:Food Deprivation / Q000502:physiology; D008297:Male; D051381:Rats; D011919:Rats, Inbred Strains; D012527:Satiation / Q000187:drug effects*; D012528:Satiety Response / Q000187:drug effects* / Q000502:physiology; D012844:Sincalide / Q000494:pharmacology*; D013395:Sucrose / Q000008:administration & dosage; D013997:Time Factors
D013395:Sucrose; D012844:Sincalide