Failure of decreased serotonin uptake or monoamine oxidase inhibition to block the acceleration in brain 5-hydroxyindole synthesis that follows food consumption.

The acceleration in brain serotonin synthesis produced by injecting rats with tryptophan or allowing them to consume a carbohydrate diet was not blocked by the prior elevation of brain serotonin levels (by administration of a MAO inhibitor: Lilly 51641) or by a treatment (chlorimipramine administration) that decreases impulse flow along serotoninergic neurons.