Perturbation of monoamine metabolism and enhanced fear responses in mice defective in the regeneration of tetrahydrobiopterin

Katsuya Miyajima, Yusuke Sudo, Sho Sanechika, Yoshitaka Hara, Mieko Horiguchi, Feng Xu, Minori Suzuki, Satoshi Hara, Koichi Tanda, Ken ichi Inoue, Masahiko Takada, Nozomu Yoshioka, Hirohide Takebayashi, Masayo Mori-Kojima, Masahiro Sugimoto, Chiho Sumi-Ichinose, Kazunao Kondo, Keizo Takao, Tsuyoshi Miyakawa, Hiroshi Ichinose

研究成果: ジャーナルへの寄稿学術論文査読

1 被引用数 (Scopus)


Increasing evidence suggests the involvement of peripheral amino acid metabolism in the pathophysiology of neuropsychiatric disorders, whereas the molecular mechanisms are largely unknown. Tetrahydrobiopterin (BH4) is a cofactor for enzymes that catalyze phenylalanine metabolism, monoamine synthesis, nitric oxide production, and lipid metabolism. BH4 is synthesized from guanosine triphosphate and regenerated by quinonoid dihydropteridine reductase (QDPR), which catalyzes the reduction of quinonoid dihydrobiopterin. We analyzed Qdpr−/− mice to elucidate the physiological significance of the regeneration of BH4. We found that the Qdpr−/− mice exhibited mild hyperphenylalaninemia and monoamine deficiency in the brain, despite the presence of substantial amounts of BH4 in the liver and brain. Hyperphenylalaninemia was ameliorated by exogenously administered BH4, and dietary phenylalanine restriction was effective for restoring the decreased monoamine contents in the brain of the Qdpr−/− mice, suggesting that monoamine deficiency was caused by the secondary effect of hyperphenylalaninemia. Immunohistochemical analysis showed that QDPR was primarily distributed in oligodendrocytes but hardly detectable in monoaminergic neurons in the brain. Finally, we performed a behavioral assessment using a test battery. The Qdpr−/− mice exhibited enhanced fear responses after electrical foot shock. Taken together, our data suggest that the perturbation of BH4 metabolism should affect brain monoamine levels through alterations in peripheral amino acid metabolism, and might contribute to the development of anxiety-related psychiatric disorders. (Figure presented.). Cover Image for this issue:

ジャーナルJournal of neurochemistry
出版ステータス出版済み - 04-2022

All Science Journal Classification (ASJC) codes

  • 生化学
  • 細胞および分子神経科学


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