Structural specificity of the carrier for L-tryptophan in rat cerebral cortex slices.

The effect of a number of commonly occurring amino acids as well as metabolites originating in the pyrrolase pathway of tryptophan catabolism and in the serotonin pathway have been studied with regard to their effect on the net flux of tryptophan into rat brain cerebral cortex slices. Phenylalanine, p-chlorophenylalanine, tyrosine, 3,4-dihydroxyphenylalanine and kynurenine as well as leucine, isoluecine and valine all inhibited the net uptake of tryptophan. It was concluded from these studies that tryptophan is transported into the cell via the large neutral amino acid carrier. Compounds lacking the aliphatic side chain carboxyl or alpha-amino group have no action on tryptophan transport.