Cholecystokinin decreases sucrose intake in chronic decerebrate rats

The capacity of chronic decerebrate rats to reduce their intake of an orally infused sucrose solution in response to peripherally administered cholecystokinin octapeptide (CCK-8) was investigated. The sucrose intake of both 24-h food-deprived chronic decerebrate rats and pair-fed control rats was reduced by CCK-8 relative to the intake after desulfated CCK-8. The intake-reducing effect of CCK-8 in the chronic decerebrate rat provides compelling evidence that the caudal brain stem is of sufficient neural complexity to mediate this response. Although others have hypothesized that connections between the caudal brain stem and forebrain are required to mediate this effect(s) of CCK-8, our results demonstrate that these pathways are not necessary.