Abstract
In mice fed on a vitamin B_6 deficient diet, even in the cases which had no remarkable symptoms of the deficiency, the activity of brain glutamic acid decarboxylase was markedly low. In rats, however, the amounts of glutamic acid, γ-aminobutyric acid and aspartic acid in the brain were not affected by vitamin B_6 deficiency. Addition of chlorpromazine to a cell-free preparation of the brain homogenate caused an increase of the enzymatic activity. The amount of brain glutamic acid decreased by an administration of chlorpromazine, while the substance exerted no effect on the amounts of γ-aminobutyric acid and aspartic acid. In vitamin B_6 deficiency, the hypnotic effect of chlorpromazine was lowered markedly in both mice and rats. These results were discussed in the point of view of central depression due to decarboxylation of glutamic acid in the brain.
