Rats injected daily with cholecystokinin initially inhibited food intake in the first 30 min after injection, but after several days showed an increase in food ingested to an amount that approached their preinjection baseline food intakes and that did not differ from that of rats injected with isotonic saline. This effect occurred with the synthetic C-terminal octapeptide of cholecystokinin and to a lesser extent with injections of natural cholecystokinin extract. It occurred with wet mash and to a lesser extent with liquid diets. When injections were spaced at twice per week, there was an inconsistent response to cholecystokinin but no evidence of habituation. This finding of possible habituation and inconsistent responding to repeated injections of cholecystokinin questions its role as a physiological satiety signal.
ASJC Scopus subject areas
- Experimental and Cognitive Psychology
- Behavioral Neuroscience