Calcium-permeable AMPA-kainate receptors in fusiform cerebellar glial cells.
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.
Burnashev
N
N
Max-Planck-Institut für Medizinische Forschung, Abteilung Zellphysiologie, Heidelberg, Germany.
Khodorova
A
A
Jonas
P
P
Helm
P J
PJ
Wisden
W
W
Monyer
H
H
Seeburg
P H
PH
Sakmann
B
B
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*
D002118:Calcium; D005971:Glutamates; D012333:RNA, Messenger; D018092:Kainic Acid Receptors; D017981:Receptors, Neurotransmitter