Neurotransmitter alterations associated with feeding and satiety.

Chronically malnourished rats were sacrificed in a food-deprived state, following eating a small amount of food, or following feeding to satiation. Regional analysis of brain neurotransmitter, neurotransmitter precursor and metabolite concentrations revealed significantly elevated levels of dopamine metabolites in the corpus striatum and nucleus accumbens of the satiated rats. Food-deprived and both refed groups exhibited elevated concentrations of the serotonin metabolite, 5-hydroxyindoleacetic acid, in most brain areas examined. These results suggest increased metabolism of dopamine to be associated with satiety rather than with the act of feeding alone. Increased serotonin metabolism appears to reflect overall nutritional status rather than the onset of satiety.