title: Identification of 3,4-didehydroretinal isomers in the Xenopus tadpole tail fin containing photosensitive melanophores.
abstract: It is well characterized that melanophores in the tail fin of Xenopus laevis tadpoles are directly photosensitive. In order to better understand the mechanism underlying this direct photosensitivity, we performed a retinal analysis of the tail fins and eyes of Xenopus tadpoles at stages 51-56 using high performance liquid chromatography (HPLC). Following the extraction of retinoids by the formaldehyde method, a fraction containing retinal and/or 3,4-didehydroretinal isomers from the first HPLC analysis were collected. These isomers were then reduced by sodium borohydride to convert retinal and/or 3,4-didehydroretinal isomers into the corresponding retinol isomers to prepare for a second HPLC analysis. Peaks of 11-cis and all-trans 3,4-didehydroretinol were detected in the eyes and tail fins containing melanophores, but they were not detected in the tail fins without melanophores. The amounts of 11-cis and all-trans 3,4-didehydroretinol were 27.5 and 5.7 fmol/fin, respectively, and the total quantity of 3,4-didehydroretinal was calculated at approximately 5 x 10(6) molecules/melanophore. These results strongly suggest the presence of 11-cis and all-trans 3,4-didehydroretinal in melanophores of the tadpole tail fin, which probably function as the chromophore of photoreceptive molecules.
authors.affiliation: Department of Life Environment, Graduate School of Human Culture, Nara Women's University, Kitauoyanishi-machi, Nara 630-8506, Japan.
authors.forename: Keiko
authors.initials: K
authors.lastname: Okano
authors.forename: Tadashi
authors.initials: T
authors.lastname: Oishi
authors.forename: Yoko
authors.initials: Y
authors.lastname: Miyashita
authors.forename: Tsuneo
authors.initials: T
authors.lastname: Moriya
authors.forename: Motoyuki
authors.initials: M
authors.lastname: Tsuda
authors.forename: Toshiaki
authors.initials: T
authors.lastname: Irie
authors.forename: Nobuo
authors.initials: N
authors.lastname: Ueki
authors.forename: Takaharu
authors.initials: T
authors.lastname: Seki
mesh_terms: D000818:Animals; D002851:Chromatography, High Pressure Liquid; D005123:Eye / Q000737:chemistry; D007536:Isomerism; D007814:Larva / Q000033:anatomy & histology / Q000737:chemistry* / Q000166:cytology*; D008547:Melanophores / Q000737:chemistry*; D010777:Photochemistry; D013623:Tail / Q000737:chemistry / Q000166:cytology; D014801:Vitamin A / Q000031:analogs & derivatives / Q000737:chemistry* / Q000302:isolation & purification*; D014982:Xenopus laevis / Q000254:growth & development
chemical_list: C024366:vitamin A2; D014801:Vitamin A