Details

Autor(en) / Beteiligte

• VARGA, V
• JANAKY, R
• HOLOPAINEN, I
• SARANSAARI, P
• OJA, S. S

Titel

Effect of magnesium on calcium influx activated by glutamate and its agonists in cultured cerebellar granule cells

Ist Teil von

• Neurochemical research, 1992-12, Vol.17 (12), p.1195-1200

Ort / Verlag

New York, NY: Springer

Erscheinungsjahr

1992

Quelle

SpringerLINK Contemporary (Konsortium Baden-Württemberg)

Beschreibungen/Notizen

• The effects of Mg2+ on the glutamate-, kainate-, N-methyl-D-aspartate- and quisqualate-induced influx of 45Ca2+ were studied in cultured cerebellar granule cells. The N-methyl-D-aspartate- and quisqualate-evoked influx was totally and the kainate- and glutamate-evoked influx partially blocked in 1.3 mM extracellular Mg2+. The increase in influx induced by kainate, quisqualate and glutamate was maximal at 0.1 mM Mg2+, whereas N-methyl-D-aspartate was most effective in totally Mg(2+)-free media. D-2-Amino-5-phosphonovalerate blocked partially and phencyclidine completely the enhancement of Ca2+ influx by 1 mM quisqualate in 0.1-mM Mg2+ medium. The effect of 10 microM quisqualate was also significantly inhibited by antagonists specific for different glutamate receptor subtypes, including N-methyl-D-aspartate, (RS) alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionate and metabotropic receptors. This evidences a heterogeneous action of quisqualate, mediated by different glutamate receptor subtypes in 0.1 mM Mg2+ medium. The efficacy of quisqualate in inducing influx of Ca2+ and the selectivity of antagonists for different receptors are also modified by extracellular Mg2+.