title: Calcium-permeable AMPA-kainate receptors in fusiform cerebellar glial cells.
abstract: Glutamate-operated ion channels (GluR channels) of the L-alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA)-kainate subtype are found in both neurons and glial cells of the central nervous system. These channels are assembled from the GluR-A, -B, -C, and -D subunits; channels containing a GluR-B subunit show an outwardly rectifying current-voltage relation and low calcium permeability, whereas channels lacking the GluR-B subunit are characterized by a doubly rectifying current-voltage relation and high calcium permeability. Most cell types in the central nervous system coexpress several subunits, including GluR-B. However, Bergmann glia in rat cerebellum do not express GluR-B subunit genes. In a subset of cultured cerebellar glial cells, likely derived from Bergmann glial cells. GluR channels exhibit doubly rectifying current-voltage relations and high calcium permeability, whereas GluR channels of cerebellar neurons have low calcium permeability. Thus, differential expression of the GluR-B subunit gene in neurons and glia is one mechanism by which functional properties of native GluR channels are regulated.
authors.affiliation: Max-Planck-Institut für Medizinische Forschung, Abteilung Zellphysiologie, Heidelberg, Germany.
authors.forename: N
authors.initials: N
authors.lastname: Burnashev
authors.forename: A
authors.initials: A
authors.lastname: Khodorova
authors.forename: P
authors.initials: P
authors.lastname: Jonas
authors.forename: P J
authors.initials: PJ
authors.lastname: Helm
authors.forename: W
authors.initials: W
authors.lastname: Wisden
authors.forename: H
authors.initials: H
authors.lastname: Monyer
authors.forename: P H
authors.initials: PH
authors.lastname: Seeburg
authors.forename: B
authors.initials: B
authors.lastname: Sakmann
mesh_terms: D000818:Animals; D002118:Calcium / Q000378:metabolism*; D002463:Cell Membrane Permeability; D002478:Cells, Cultured; D002531:Cerebellum / Q000502:physiology*; D015870:Gene Expression; D005971:Glutamates / Q000502:physiology; D066298:In Vitro Techniques; D015640:Ion Channel Gating; D009457:Neuroglia / Q000502:physiology*; D009693:Nucleic Acid Hybridization; D012333:RNA, Messenger / Q000235:genetics; D051381:Rats; D018092:Kainic Acid Receptors; D017981:Receptors, Neurotransmitter / Q000502:physiology*
chemical_list: D002118:Calcium; D005971:Glutamates; D012333:RNA, Messenger; D018092:Kainic Acid Receptors; D017981:Receptors, Neurotransmitter