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RESEARCH PRODUCT

Effects of L-tyrosine and L-tryptophan on the cardiovascular and endocrine system in humans

subject

description

Brain catecholamine and serotonin neurons are intimately involved in a number of relevant physiological functions such as cardiovascular regulation, neuroendocrine output from the anterior pituitary (e.g. ACTH, prolactin), regulation of behavior (e.g. aggression, sleep, locomotor and sexual behavior), mood or appetite control [1–5]. The modification of transmitter synthesis and release appears to be remarkably correlated with the subsequent physiological changes observed. While there are numerous pharmacological approaches that affect the respective neurotransmitter products (i.e. the catecholamines dopamine, noradrenaline and adrenaline and the indoleamine serotonin), one particular attractive (while specific) approach is the administration of a precursor amino acid. It is thus a prerequisite for the physiological and possibly therapeutical properties of the precursor amino acids L-tyrosine and L-tryptophan that they affect synthesis and release of their transmitter product. For the understanding of the nature of the different physiological responses some of the neurochemical mechanism guiding the transmitter synthesis need to be briefly described.