Peripherally administered tetrahydrobiopterin increases in vivo tryptophan hydroxylase activity in the striatum after transplantation of fetal ventral mesencephalon in six hydroxydopamine lesioned rats

• Published in: Neuroscience letters 1998-08, Vol.253 (1), p.45-48
• Main Authors: Ishida, Yasushi, Todaka, Kazunari, Kuwahara, Itsumi, Hashiguchi, Hiroyuki, Ishizuka, Yuta, Nakane, Hideyuki, Mitsuyama, Yoshio
• Format: Article
• Language: English
• Subjects: 5-Hydroxytryptophan; 5-Hydroxytryptophan - metabolism; 6 R-Tetrahydrobiopterin; 6-Hydroxydopamine; Animals; Antioxidants - administration & dosage; Antioxidants - pharmacokinetics; Antioxidants - pharmacology; Biological and medical sciences; Biopterins - administration & dosage; Biopterins - analogs & derivatives; Biopterins - pharmacokinetics; Biopterins - pharmacology; Brain Tissue Transplantation - physiology; Corpus Striatum - drug effects; Corpus Striatum - enzymology; Corpus Striatum - physiology; Denervation; Development. Senescence. Regeneration. Transplantation; Embryo, Mammalian; Female; Fetal Tissue Transplantation - physiology; Functional Laterality; Fundamental and applied biological sciences. Psychology; Injections, Intraperitoneal; Mesencephalon - physiology; Mesencephalon - transplantation; Methamphetamine - pharmacology; Microdialysis; Motor Activity - drug effects; Motor Activity - physiology; Oxidopamine; Prosencephalon - drug effects; Prosencephalon - pathology; Prosencephalon - physiology; Rats; Rats, Wistar; Rotation; Striatum; Transplants; Tryptophan hydroxylase; Tryptophan Hydroxylase - metabolism; Vertebrates: nervous system and sense organs
• ISSN: 0304-3940; 1872-7972
• DOI: 10.1016/S0304-3940(98)00601-6

The intraperitoneal administration of 6 R- l-erythro-5,6,7,8-tetrahydrobiopterin (6 R-BH 4), a natural cofactor for tyrosine hydroxylase and tryptophan hydroxylase (TRH), dose-dependently increased the extracellular concentration of 6 R-BH 4 itself in rat striatum. The concentration was investigated by in vivo microdialysis and measured simultaneously with 5-hydroxytryptophan (5-HTP), a precursor of serotonin, by high performance liquid chromatography with electrochemical detection. The 6 R-BH 4 (50 mg /kg, i.p.) administration increased the accumulation of 5-HTP as an index of in vivo TRH activity under the inhibition of aromatic l-amino acid decarboxylase by NSD-1015 in the striatum of both normal control and 6-hydroxydopamine lesioned rats with intrastriatal transplants of fetal ventral mesencephalon (VM). The results suggest that TRH in the striatum of both control and VM-grafted rats is activated by 6 R-BH 4 penetrating into the brain from the blood.