ISSN:
1573-6903
Keywords:
Calcium influx
;
cultured cerebellar granule cells
;
glutamate
;
kainate
;
quisqualate
;
magnesium ions
Source:
Springer Online Journal Archives 1860-2000
Topics:
Medicine
Notes:
Abstract The effects of Mg2+ on the glutamate-, kainate-, N-methyl-d-aspartate- and quisqualate-induced influx of45Ca2+ 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 Mg2+-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 μM quisqualate was also significantly inhibited by antagonists specific for different glutamate receptor subtypes, including N-methyl-d-aspartate, (RS)α-amino-3-hydroxy-5-methyl-4-isozazolepropionate and metabotropic recptors. 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 Ca+ and the selectivity of antagonists for different receptors are also modified by extracellular Mg2+.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00968399
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