Spontaneous glutamate release by a "fibrous"-like cerebellar astroglial cell clone.
To investigate the role of astrocytes in the metabolism of glutamate, the neurotransmitter of the granule cells of the cerebellar cortex, we have analyzed various parameters related to the synthesis of glutamate in astroglial cell clones that may be the in vitro counterparts of the cerebellar astrocytes. The "fibrous"-like clone spontaneously released large quantities of glutamate, even in the absence of glutamine in the culture medium, but did not release alanine. In contrast, the "Golgi-Bergmann"-like cells released alanine but not glutamate, whereas the "velate-protoplasmic"-like astrocytes released little glutamate and alanine. However, the glutamate oxaloacetate transaminase and glutamate pyruvate transaminase activities of the three astroglial cell lines, measured in the direction of glutamate synthesis, were comparable. In addition, the "velate protoplasmic" and "Golgi-Bergmann" clones did not consume glutamine present at 2 mM in the culture medium. These data suggest that the different types of in vivo cerebellar astrocytes may have distinct roles regarding glutamate-glutamine metabolism.
Cambier
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INSERM U178, Unité de Recherches sur la Différenciation et la Neuroendocrinologie de Cellules Digestives, Villejuif, France.
Pessac
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D000409:Alanine / Q000378:metabolism; D000410:Alanine Transaminase / Q000378:metabolism; D000818:Animals; D001219:Aspartate Aminotransferases / Q000378:metabolism; D001253:Astrocytes / Q000201:enzymology / Q000378:metabolism*; D002531:Cerebellum / Q000166:cytology / Q000378:metabolism*; D002999:Clone Cells; D003470:Culture Media; D005971:Glutamates / Q000378:metabolism*; D018698:Glutamic Acid; D005973:Glutamine / Q000378:metabolism; D051379:Mice
D003470:Culture Media; D005971:Glutamates; D005973:Glutamine; D018698:Glutamic Acid; D001219:Aspartate Aminotransferases; D000410:Alanine Transaminase; D000409:Alanine