Influence of B vitamins on binding properties of serotonin receptors in the CNS of rats.

Treatment of normal adult rats with pyridoxine or a B-vitamin mixture resembling Neurobion 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. The results also suggest a continuum from deficiency in pyridoxine to treatment of animals with a moderate excess of pyridoxine which is reflected in the synthesis and secretion into the synaptic cleft of the neurotransmitter serotonin.