Glutamate agonists release excitatory aminoacids from rat astrocytes.
Astrocytes release glutamate (Glu) by the mobilisation of intracellular concentrations of Ca++. The rationale of the present work was to test whether Glu and its agonists, known to affect intracellular Ca++ content via the activation of metabotropic and ionotropic receptors, could modulate the astrocytic release of excitatory aminoacids. NMR experiments showed that Glu released uniformly labelled [13C] Glu in the incubation medium of rat astrocytes in primary cultures. Further experiments confirmed this finding and showed that the incubation of these cells with agonists and antagonists of Glu ionotropic and metabotropic receptors, produced a different modulation of Glu and aspartate release. The observed activations of the various receptors suggest a complex modulation of the release of the excitatory aminoacids. Such a release of is interpreted in terms of metabolic microzonation.
Romestaing
C
C
CNRS UMR 5123, Campus La Doua, Bät Raphaël Dubois, 69622 Villeurbanne, France. cromestaing@hotmail.com
Denoroy
L
L
Parrot
S
S
Martin
V
V
Leviel
V
V
Vega
C
C
Massarelli
R
R
D000818:Animals; D001224:Aspartic Acid / Q000378:metabolism*; D001253:Astrocytes / Q000187:drug effects* / Q000378:metabolism*; D002478:Cells, Cultured; D018690:Excitatory Amino Acid Agonists / Q000494:pharmacology*; D018698:Glutamic Acid / Q000378:metabolism*; D009682:Magnetic Resonance Spectroscopy; D051381:Rats; D017207:Rats, Sprague-Dawley
D018690:Excitatory Amino Acid Agonists; D001224:Aspartic Acid; D018698:Glutamic Acid