Ineffectiveness of cholecystokinin in impairing runway performance.
We compared changes in runway performance by rats for sucrose reward following injections of the synthetic C-terminal octapeptide of cholecystokinin (CCK-8) with those seen after variations in food deprivation and injections of lithium chloride. No effects on running for either 10% or 30% sucrose were found following 0.5 to 4.0 micrograms/kg of CCK-8, though such doses suppressed 30-min sucrose intake up to 53%. Statistically reliable slowing of running for 10% sucrose was observed on two series of tests after 8.0 micrograms/kg of CCK-8. Running for 30% sucrose was not significantly affected by this dose. The general ineffectiveness of CCK-8 for producing decrements in running spread contrasts with significantly reduced performance after either reductions in food deprivation (21 h vs 12 and 3 h) or injections of 75 mg/kg lithium chloride. These results suggest that the mode of action of CCK-8 in reducing food intake is different than that produced by changes in hunger or by non-specific interference with motivation by malaise. The finding that CCK-8 can substantially reduce consumption with no apparent changes in appetitive motivation is consistent with the hypothesis that this substance acts only late in the meal to prematurely trigger satiety.
D000818:Animals; D001066:Appetite / Q000187:drug effects; D005247:Feeding Behavior / Q000187:drug effects; D005508:Food Deprivation; D008297:Male; D051381:Rats; D011919:Rats, Inbred Strains; D012527:Satiation / Q000187:drug effects*; D012528:Satiety Response / Q000187:drug effects*; D012844:Sincalide / Q000494:pharmacology*
D012844:Sincalide