Possible Interaction: Dopamine and Tyrosine

“Under these study conditions, phenylalanine and tyrosine depletion may have larger effects on dopamine than noradrenaline.”

“Rationale: Tyrosine depletion has been shown to reduce dopamine over activity in animal and human investigations.”

“ResultsWe compare the variations in serotonin and dopamine synthesis due to meals and find that dopamine synthesis is insensitive to the availability of tyrosine but serotonin synthesis is sensitive to the availability of tryptophan.”

“Thus, for example, brain levels of tryptophan, tyrosine , or choline can control the rates at which neurons synthesize serotonin, dopamine , or acetylcholine, respectively.”

“The production of DA by HAE cells was increased with time in the presence of L-tyrosine and BH(4), and was abolished with a specific TH inhibitor, alpha-methyl-rho-tyrosine.”

“Oxygenation of L-tyrosine occurred only in the presence of dopamine as co-substrate.”

“For example, the CNS turnover of two catecholamine neurotransmitters, dopamine and norepinephrine, can be altered by ingestion of their amino acid precursor, tyrosine , when neurons that release these monoamines are firing frequently.”

“In turn, tyrosine is important in the production of many neurotransmitters, such as dopamine and serotonin.”

“The fact that tyrosine increases dopamine availability that, in turn, may enhance cognitive performance has led to numerous studies on healthy young participants taking tyrosine as a food supplement.”

“… TYR … DA level in the brain, we investigated, in a double-blind, randomized, placebo-controlled design, whether the C957T genotypes of a functional synonymous polymorphism in … TYR-induced performance differences on inhibiting behavioral responses in a stop-signal task and working memory (WM) updating in a N-back task.”