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Glutamate transporter type 3 attenuates the activation of N-methyl-D-aspartate receptors co-expressed in Xenopus oocytes.
Zuo, Zhiyi; Fang, Hongyu.
Afiliação
  • Zuo Z; Department of Anesthesiology, University of Virginia Health System, Charlottesville, Virginia 22908-0710, USA. zz3c@virginia.edu
J Exp Biol ; 208(Pt 11): 2063-70, 2005 Jun.
Article em En | MEDLINE | ID: mdl-15914650
We studied the regulation of N-methy-D-aspartate receptor (NMDAR) current/activation by glutamate transporter type 3 (EAAT3), a neuronal EAAT in vivo, in the restricted extracellular space of a biological model. This model involved co-expressing EAAT3 and NMDAR (composed of NMDAR1-1a and NMDAR2A) in Xenopus oocytes. The NMDAR current was reduced in the co-expression oocytes but not in oocytes expressing NMDAR only when the flow of glutamate-containing superfusate was stopped. The degree of this current reduction was glutamate concentration-dependent. No reduction of NMDAR current was observed in Na+-free solution or when NMDA, a non-substrate for EAATs, was used as the agonist for NMDAR. In the continuous flow experiments, the dose-response curve of glutamate-induced current was shifted to the right-hand side in co-expression oocytes compared with oocytes expressing NMDAR alone. The degree of this shift depended on the abundance of EAAT3 in the co-expression oocytes. Thus, the glutamate concentrations sensed by NMDAR locally were lower than those in the superfusates. These results suggest that EAAT3 regulates the amplitude of NMDAR currents at pre-saturated concentrations of glutamate to EAAT3. Thus, EAATs, by rapidly regulating glutamate concentrations near NMDAR, modulate NMDAR current/activation.
Assuntos
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Base de dados: MEDLINE Assunto principal: Receptores de N-Metil-D-Aspartato / Sistema X-AG de Transporte de Aminoácidos / Simportadores Limite: Animals Idioma: En Revista: J Exp Biol Ano de publicação: 2005 Tipo de documento: Article País de afiliação: Estados Unidos
Buscar no Google
Base de dados: MEDLINE Assunto principal: Receptores de N-Metil-D-Aspartato / Sistema X-AG de Transporte de Aminoácidos / Simportadores Limite: Animals Idioma: En Revista: J Exp Biol Ano de publicação: 2005 Tipo de documento: Article País de afiliação: Estados Unidos