title: Regulation of the Na+-dependent glutamate/aspartate transporter in rodent cerebellar astrocytes.
abstract: The regulation of the Na+-dependent glutamate/aspartate transporter system GLAST expressed in rat and mouse cerebellar and cortical astrocytic cultures was examined. Pretreatment of the cerebellar cells with L-glutamate and 12-O-tetradecanoyl-phorbol-13-acetate (TPA), a known Ca2+/diacylglicerol-dependent protein kinase (PKC) activator, produced a decrease in [3H]-D-aspartate uptake. This reduction was dose- and time-dependent and sensitive to PKC inhibitors. Furthermore, the L-glutamate-dependent [3H]-D-aspartate uptake decrease is a non-receptor dependent process, because neither of the agonists or antagonists were effective in mimicking or reverting the effect. Interestingly, transportable substrates could reproduce the L-glutamate effect. In sharp contrast, in cortical astrocytes, both L-glutamate and TPA pre-exposure result in an augmentation of the [3H]-D-aspartate uptake. These findings suggest that the Na+-dependent glutamate uptake GLAST undergoes a region-specific regulation.
authors.affiliation: Departamento de Genética y Biología Molecular, Cinvestav-IPN, Apartado Postal 14-740 México, DF, 07000, México.
authors.forename: Alfonso
authors.initials: A
authors.lastname: Bernabé
authors.forename: J Alfredo
authors.initials: JA
authors.lastname: Méndez
authors.forename: L Clara R
authors.initials: LC
authors.lastname: Hernández-Kelly
authors.forename: Arturo
authors.initials: A
authors.lastname: Ortega
mesh_terms: D027322:Amino Acid Transport System X-AG / Q000378:metabolism*; D000818:Animals; D001253:Astrocytes / Q000187:drug effects / Q000378:metabolism*; D002478:Cells, Cultured; D002531:Cerebellum / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D051379:Mice; D051381:Rats; D012964:Sodium / Q000378:metabolism*; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology
chemical_list: D027322:Amino Acid Transport System X-AG; D012964:Sodium; D013755:Tetradecanoylphorbol Acetate