Glutamate-induced cytoplasmic Ca2+ transients in neurones isolated from the rat dorsal cochlear nucleus.
Gen Physiol Biophys
; 23(1): 3-20, 2004 Mar.
Article
en En
| MEDLINE
| ID: mdl-15270126
Extracellular application of glutamate elicited cytoplasmic Ca2+ transients in freshly dissociated rat neurones of the dorsal cochlear nucleus (DCN) (identified as pyramidal cells) with half-maximal concentration of 513 micromol/l while saturating doses (5 mmol/l) of this neurotransmitter caused transients of 46.1 +/- 3.0 nmol/l on an average. The genesis of these glutamate-evoked Ca2+ transients required extracellular Ca2+. When [Mg2+]o was 1 mmol/l, the NMDA receptor antagonist AP5 (100 micromol/l) had no effects while 100 micromol/l CNQX and 10 micromol/l NBQX, inhibitors of the AMPA receptors, greatly decreased the glutamate-induced Ca2+ transients (a decrease of 92 and 57%, respectively). When facilitating the activation of the NMDA receptors (50 micromol/l glycine, 20 micromol/l [Mg2+]o) in the presence of 100 micromol/l CNQX, Ca2+ transients of 55.4 +/- 13.1 nmol/l could be produced. Block of the voltage-gated Ca2+ channels (200 micromol/l Cd2+) decreased the Ca2+ transients to approx. 50%. The data indicate that under our control experimental circumstances the glutamate-induced Ca2+ transients of the isolated DCN neurones are produced mainly by Ca2+ entry through voltage-gated Ca2+ channels and AMPA receptors. However, when the activation of the NMDA receptors may take place, these receptors also contribute significantly to the genesis of the glutamate-evoked cytoplasmic [Ca2+] elevations.
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Colección:
01-internacional
Base de datos:
MEDLINE
Asunto principal:
Núcleo Coclear
/
Ácido Glutámico
/
Señalización del Calcio
/
Neuronas
Límite:
Animals
Idioma:
En
Revista:
Gen Physiol Biophys
Año:
2004
Tipo del documento:
Article
País de afiliación:
Hungria
Pais de publicación:
Eslovaquia