Voltage-gated sodium and potassium channels in radial glial cells of trout optic tectum studied by patch clamp analysis and single cell RT-PCR

Autor(en): Rabe, H
Koschorek, E
Nona, SN
Ritz, HJ
Jeserich, G
Stichwörter: ASTROCYTES IN-SITU; bony fish; CURRENTS; DEVELOPMENTAL REGULATION; EXPRESSION; HIPPOCAMPAL ASTROCYTES; ION CHANNELS; K+ CHANNEL; NA+ CHANNELS; Neurosciences; Neurosciences & Neurology; radial glia; RAT; SCHWANN-CELLS; shaker-related channels; single-cell RT-PCR; sodium channels; visual center
Erscheinungsdatum: 1999
Herausgeber: WILEY-LISS
Journal: GLIA
Volumen: 26
Ausgabe: 3
Startseite: 221
Seitenende: 232
Radial glial cells in the visual center of trout were analyzed immunocytochemically and with the whole cell mode of the patch-clamp technique in combination with RT-PCR. By immunostaining with anti-GFAP antibodies radially oriented cell processes spanning the entire width of the tectum were brightly labeled, while with anti-S-100 antiserum the cell bodies residing in a discrete layer close to the ventricular border became most clearly visible. Virtually all radial glial cells examined in brain slices exhibited voltage-gated sodium inward currents that were activated above -40 mV, blocked by micromolar concentrations of TTX and totally eliminated if sodium was substituted for Tris in the bath solution. In contrast with adjacent nerve cells of the same slices radial glial cells did not exhibit spontaneous electrical activity and could not be stimulated to generate action potentials by depolarizing current injections. Two types of voltage-gated potassium outward currents were elicited by depolarizing voltage steps: a sustained current with delayed rectifier properties and a superimposed transient ``A''-type current, both being activated at a threshold potential of -40 mV. In cultured radial glial cells subtle differences were noticed regarding current density, inactivation kinetics, and TEA-sensitivity of the potassium currents. Inwardly rectifying potassium currents activating at hyperpolarized voltages were not observed. By single cell RT-PCR the transcripts of two shaker-related potassium channel genes (termed tsha1-a fish homologue to Kv1.2- and tsha3) were amplified, while transcripts for tsha 2 and tsha 4 were not detected. (C) 1999 Wiley-Liss, Inc.
ISSN: 08941491
DOI: 10.1002/(SICI)1098-1136(199905)26:3<221::AID-GLIA4>3.0.CO;2-A

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