Glutamate-activated ionic currents in cultured astrocytes from trout: evidence for the occurrence of non-N-methyl-D-aspartate receptors.
Glutamate-induced currents were recorded from cultured trout astrocytes with the whole-cell variation of the patch-clamp technique. Ninety percent of the tested cells were directly depolarized by the amino acid neurotransmitter in a concentration-dependent manner. The depolarizing effect was due to an inward current that reversed near 0 mV and was accompanied by a noise increase, indicating the opening of an ion channel. Ion substitution experiments revealed that the glutamate-induced current was mainly carried by sodium ions but not chloride or calcium ions. The glutamate-induced response could be mimicked by the neuronal glutamate receptor subtype agonists kainate and quisqualate, while N-methyl-D-aspartate was without detectable effect.
Clasen
T
T
Abt. Zoophysiologie, Universität Osnabrück, Germany.
Jeserich
G
G
Krüppel
T
T
D000818:Animals; D001253:Astrocytes / Q000187:drug effects / Q000378:metabolism*; D002478:Cells, Cultured; D018698:Glutamic Acid / Q000494:pharmacology*; D007150:Immunohistochemistry; D007473:Ion Channels / Q000187:drug effects / Q000378:metabolism*; D008564:Membrane Potentials / Q000187:drug effects; D017686:Oncorhynchus mykiss / Q000378:metabolism*; D018408:Patch-Clamp Techniques; D016194:Receptors, N-Methyl-D-Aspartate / Q000187:drug effects / Q000378:metabolism*
D007473:Ion Channels; D016194:Receptors, N-Methyl-D-Aspartate; D018698:Glutamic Acid