title: Ontogenic changes of kynurenine aminotransferase I activity and its expression in the chicken retina.
abstract: Kynurenine aminotransferases are key enzymes for the synthesis of kynurenic acid (KYNA), an endogenous glutamate receptor antagonist. The study described here examined ontogenic changes of kynurenine aminotransferase I (KAT I) activity and its expression in the chicken retina. KAT I activity measured on embryonic day 16 (E16) was significantly higher than at all other stages (E12, P0 and P7). Double labeling with antibodies against glutamine synthetase showed that on P7 KAT I was expressed in Müller cell endfeet and their processes in the inner retina. Since KAT I activity is high in the late embryonic stages, it is conceivable that it plays a neuromodulatory role in the retina during the late phase of embryogenesis.
authors.affiliation: Department of Pathophysiology of Vision and Neuro-Ophthalmology, Division of Experimental Ophthalmology, University Eye Hospital, Röntgenweg 11, D-72076 Tübingen, Germany. rrejdak@yahoo.com
authors.forename: Robert
authors.initials: R
authors.lastname: Rejdak
authors.forename: Elzbieta
authors.initials: E
authors.lastname: Zielinska
authors.forename: Yana
authors.initials: Y
authors.lastname: Shenk
authors.forename: Waldemar A
authors.initials: WA
authors.lastname: Turski
authors.forename: Etsuo
authors.initials: E
authors.lastname: Okuno
authors.forename: Tomasz
authors.initials: T
authors.lastname: Zarnowski
authors.forename: Zbigniew
authors.initials: Z
authors.lastname: Zagorski
authors.forename: Eberhart
authors.initials: E
authors.lastname: Zrenner
authors.forename: Konrad
authors.initials: K
authors.lastname: Kohler
mesh_terms: D000818:Animals; D002642:Chick Embryo / Q000378:metabolism*; D002645:Chickens / Q000378:metabolism*; D005865:Gestational Age; D007150:Immunohistochemistry / Q000379:methods; D009024:Morphogenesis / Q000502:physiology; D012160:Retina / Q000196:embryology / Q000201:enzymology* / Q000254:growth & development*; D000637:Transaminases / Q000032:analysis / Q000378:metabolism*
chemical_list: D000637:Transaminases; C021481:kynurenine-oxoglutarate transaminase