Possible Interaction: Amphetamine and Tryptophan

“It was observed that: 1) parachlorophenylalanine prolonged the anticataleptic action of ephedrine and, in part also, that … an anticataleptic effect and enhanced somewhat the same effect of both psychostimulating drugs used, 3) d, 1-tryptophan increased the intensity of catalepsy and reduced … the anticataleptic action of ephedrine and amphetamine.”

“L-Dopa, dl-amphetamine , alpha-methyl-Dopa, parachlorophenylalanine and serotonino-blockators--deseryl and lysergide--eliminate the tranquilizing action of tryptophane on emotional reactivity, decreasing serotonin accumulation and intensifying the formation of 5-oxyindolacetic acid.”

“ Tryptophan was previously shown to increase backward walking, circling and forward walking provoked by amphetamine , but not the other three behaviours tested (Lees, Fernando and Curzon, 1979).”

“The acute administration of amphetamine also caused an increase in the concentration of tryptophan and 5-HT in the brain stem, striatum and some regions of the limbic system.”

“It is probably not due to a tryptophan-specific mechanism, because amphetamine increases the ratio of brain/plasma concentrations not only of tryptophan but also of tyrosine and phenylalanine.”