Possible Interaction: Gamma-Aminobutyric Acid 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.”

“Defective metabolism of pyridoxal 5′-phosphate PLP ), characterized by elevated serum PLP levels, results in reduced levels of the inhibitory neurotransmitter γ-aminobutyric acid (GABA) in the brain.”

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

“The results indicate that while total GABAergic peptides are not altered in several of the neurologic diseases studied, drugs such as isoniazid and/or pyridoxine can significantly elevate both free and conjugated GABA levels in human CSF.”

“The decrease in PLP production reduces the amount of GABA being produced, which, in turn, impacts the efficacy of GABAergic transmission.”

“These results indicate that pyridoxal 5'-phosphate may be associated with the inhibitory discharge of GABA in the hippocampal CA1 neurons, and the increased level of GABA may protect hippocampal CA1 pyramidal cells from ischemic damage.”

“ GABA blocked the effects of PLP on enzyme activity.”

“microinjection of the GABAergic compounds muscimol, isoguvacine, aminooxyacetic acid or GABA itself, significantly protected against PLP effects.”

“The formation of GABA was stimulated by addition of pyridoxal phosphate in the range 0.05–1 microM (0.97 ± 0.02 nmol · min−1 · mg protein-1 at a saturating cofactor concentration), which indicates that the process was catalyzed by glutamic acid decarboxylase.”

“For example, the concentration of zinc in the mossy fiber axons has been estimated to approach 300-350 microM. Both zinc and pyridoxal phosphate (PLP) deficiency and excess have been reported to produce epileptiform seizures, which are blocked by gamma-aminobutyric acid (GABA).”