title: AMPA receptors serum-dependently mediate GABAA receptor alpha1 and alpha6 subunit down-regulation in cultured mouse cerebellar granule cells.
abstract: Depolarization of cultured mouse cerebellar granule cells with potassium or kainate results in developmentally arrested state that includes down-regulation of GABA(A) receptor alpha1, alpha6 and beta2 subunit expression. These subunits are normally strongly expressed in cerebellar granule cells from second postnatal week throughout the adulthood. In the present study we demonstrate that selective activation of AMPA subtype of glutamate receptors down-regulates alpha1 and alpha6 subunit mRNA expression. Removal of AMPA agonist from culture medium restores expression of these subunits indicating reversibility of the down-regulation. In serum-free culture medium AMPA receptor activation did not down-regulate alpha1 or alpha6 subunit expression. Furthermore, the down-regulation was strongly attenuated when the cells were cultured in the presence of dialysed fetal calf serum. The results indicate that down-regulation of GABA(A) receptor alpha1 and alpha6 subunits by AMPA receptor activation is dependent on the presence of low molecular weight compounds present in fetal calf serum. In order to study mouse cerebellar granule cell maturation and/or regulation of GABA(A) receptor subunit expression in culture, the experiments should be performed in the absence of fetal calf serum.
authors.affiliation: Department of Pharmacology, Drug Development and Therapeutics, University of Turku, FIN-20014 Turku, Finland. mikko.uusi-oukari@utu.fi <mikko.uusi-oukari@utu.fi>
authors.forename: Mikko
authors.initials: M
authors.lastname: Uusi-Oukari
authors.forename: Leena-Stiina
authors.initials: LS
authors.lastname: Kontturi
authors.forename: Sampsa A
authors.initials: SA
authors.lastname: Kallinen
authors.forename: Virpi
authors.initials: V
authors.lastname: Salonen
mesh_terms: D000409:Alanine / Q000031:analogs & derivatives / Q000494:pharmacology; D000818:Animals; D002478:Cells, Cultured; D002531:Cerebellum / Q000166:cytology / Q000378:metabolism*; D004396:Coloring Agents; D016895:Culture Media, Serum-Free; D015536:Down-Regulation; D018755:GABA Agonists / Q000494:pharmacology; D018756:GABA Antagonists / Q000494:pharmacology; D058787:GABA-A Receptor Antagonists; D007608:Kainic Acid / Q000494:pharmacology; D051379:Mice; D009474:Neurons / Q000187:drug effects / Q000378:metabolism*; D011485:Protein Binding; D011744:Pyrimidinones / Q000494:pharmacology; D011810:Quinoxalines / Q000494:pharmacology; D012333:RNA, Messenger / Q000096:biosynthesis / Q000235:genetics; D018091:Receptors, AMPA / Q000037:antagonists & inhibitors / Q000235:genetics / Q000502:physiology*; D011963:Receptors, GABA-A / Q000096:biosynthesis* / Q000235:genetics; D018092:Kainic Acid Receptors / Q000037:antagonists & inhibitors; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013778:Tetrazolium Salts; D013844:Thiazoles; D000097806:GluK2 Kainate Receptor
chemical_list: D000409:Alanine; D004396:Coloring Agents; D016895:Culture Media, Serum-Free; D018755:GABA Agonists; D018756:GABA Antagonists; D058787:GABA-A Receptor Antagonists; D007608:Kainic Acid; D011744:Pyrimidinones; D011810:Quinoxalines; D012333:RNA, Messenger; D018091:Receptors, AMPA; D011963:Receptors, GABA-A; D018092:Kainic Acid Receptors; D013778:Tetrazolium Salts; D013844:Thiazoles; D000097806:GluK2 Kainate Receptor; C443679:CPW 399; C546241:Gabra1 protein, mouse; C546172:Gabra6 protein, mouse; C056723:FG 9041; C022616:thiazolyl blue