Aminoacidemias: effects on maze performance and cerebral serotonin.

The feeding of high dietary supplements of L-phenylalanine (7 percent) and L-leucine (7 percent) to weanling rats is associated with poor performance in a multiple-T, water-escape maze. Supplements high in L-tryptophan (5 percent), on the other hand, result in maze performance which is superior to that of controls. Adding 5 percent tryptophan to the high-phenylalanine diet reverses the behavioral deficit. The quality of maze performance correlated with the cerebral content of serotonin.