Possible Interaction: Serotonin and Vitamin B 6

“ Vitamin B6 plays a key role in the synthesis of several neurotransmitters, including serotonin , dopamine, norepinephrine, and gamma-aminobutyric acid, all of which have been proposed to be involved in the development of TD.”

“ Vitamin B-6 status has a significant effect on 5-HT and GABA, neurotransmitters that control pain perception, anxiety, and depression (2).”

“Investigations into these pathways led to interesting findings: brain concentrations of serotonin could be increased by supplementing the diet of rats with tryptophan and pyridoxine ; the elevated brain serotonin levels had behavioral consequences.”

“Oral doses of pyridoxine resulted in an appreciable increase in the serotonin content and a very large increase in the PLP content of blood in these hyperactive patients.”

“Since the decarboxylation of tryptophan to trypatamine and serotonia is also dependent on pyridoxine it would be interesting to know whether giving supplemental pyridoxine would protect patients on oral contraceptives from becoming depressed.”

“DA and NE were combined with PLP by a non-enzymatic reaction, whereas 5-HT was bound only slightly with PLP.”

“SummaryTreatment of normal adult rats with pyridoxine or a B-vitamin mixture resembling Neurobion® 1 led to an increase in serotonin content of various brain areas and to a decrease in the number of serotonin S2 receptors.”

“The results indicate that the pyridoxal phosphate level in regions of the brain regulates the extent of decarboxylation of 5-hydroxytryptophan, the precursor of serotonin.”

“With elevated tryptophan intake, excess pyridoxine significantly increased serotonin and 5HIAA (+32%, +20%) in the hypothalamus.”

“Pretreatment with pyridoxine blocked the Trp-induced rise in urinary 5-HIAA but not that in brain serotonin (5-hydroxytryptamine, 5HT).”