The metabolism of biogenic monoamines during embryogenesis and metamorphosis in two anuran species.
This study investigated the pathways to many monoamines and their metabolites in the central nervous system of the frog Rana nigromaculata and the toad Bufo bufo japonicus during embryonic development and metamorphosis. Metabolites were analyzed by three-dimensional HPLC. The two species provided evidence of similar pathways, with slightly different timetables for the development of their monoamine systems. During embryonic development, the main metabolic pathways in entire embryos were tyrosine (TYR)-->[3,4-dihydroxyphenylalanine in Bufo]-->3-hydroxytyramine-->norepinephrine or epinine (EPIN)-->epinephrine, TYR-->tyramine--> (octopamine in Rana) and TYR-->3-O-methyldopa for catecholamines, and tryptophan-->kynurenine and 5-hydroxytryptamine (5-HT)-->[5-hydroxyindoleacetic acid and N-methyl-5-hydroxytryptamine (N-MET) in Bufo]. The monoamine system in the brain was similar during metamorphosis to that during embryogenesis with a few exceptions. The most striking change was the development of the bufotenine (5-hydroxy-N, N-dimethyltryptamine) pathway from 5-HT via N-MET. EPIN and norepinephrine in Rana and octopamine in both species disappeared during metamorphosis. These results are discussed in relation to the roles of the various pathways in development.
Takeda
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Department of Biotechnology, COSMO Research Institute, Saitama, Japan.
D000818:Animals; D015306:Biogenic Monoamines / Q000378:metabolism*; D001921:Brain / Q000196:embryology / Q000378:metabolism; D002023:Bufo bufo; D002851:Chromatography, High Pressure Liquid; D004625:Embryo, Nonmammalian / Q000378:metabolism; D008675:Metamorphosis, Biological; D008954:Models, Biological; D011898:Ranidae
D015306:Biogenic Monoamines