Coupling of AMPA receptors with the Na + /Ca 2+ exchanger in cultured rat astrocytes

Coupling of AMPA receptors with the Na + /Ca 2+ exchanger in cultured rat astrocytes Astrocytes exhibit three transmembrane Ca 2+ influx pathways: voltage-gated Ca 2+ channels (VGCCs), the α-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid (AMPA) class of glutamate receptors, and Na + /Ca 2+ exchangers. Each of these pathways is thought to be capable of mediating a significant increase in Ca 2+ concentration ((Ca 2+ ) i ); however, the relative importance of each and their interdependence in the regulation astrocyte (Ca 2+ ) i is not known. We demonstrate here that 100 μM AMPA in the presence of 100 μM cyclothiazide (CTZ) causes an increase in (Ca 2+ ) i in cultured cerebral astrocytes that requires transmembrane Ca 2+ influx. This increase of (Ca 2+ ) i is blocked by 100 μM benzamil or 0.5 μM U-73122, which inhibit reverse-mode operation of the Na + /Ca 2+ exchanger by independent mechanisms. This response does not require Ca 2+ influx through VGCCs, nor does it depend upon a significant Ca 2+ influx through AMPA receptors (AMPARs). Additionally, AMPA in the presence of CTZ causes a depletion of thapsigargin-sensitive intracellular Ca 2+ stores, although depletion of these Ca 2+ stores does not decrease the peak (Ca 2+ ) i response to AMPA. We propose that activation of AMPARs in astrocytes can cause (Ca 2+ ) i to increase through the reverse mode operation of the Na + /Ca 2+ exchanger with an associated release of Ca 2+ from intracellular stores. This proposed mechanism requires neither Ca 2+ -permeant AMPARs nor the activation of VGCCs to be effective. http://www.deepdyve.com/assets/images/DeepDyve-Logo-lg.png Brain Research Elsevier

Coupling of AMPA receptors with the Na + /Ca 2+ exchanger in cultured rat astrocytes

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Publisher
Elsevier
Copyright
Copyright © 2000 Elsevier Science B.V.
ISSN
0006-8993
D.O.I.
10.1016/S0006-8993(00)02973-5
Publisher site
See Article on Publisher Site

Abstract

Astrocytes exhibit three transmembrane Ca 2+ influx pathways: voltage-gated Ca 2+ channels (VGCCs), the α-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid (AMPA) class of glutamate receptors, and Na + /Ca 2+ exchangers. Each of these pathways is thought to be capable of mediating a significant increase in Ca 2+ concentration ((Ca 2+ ) i ); however, the relative importance of each and their interdependence in the regulation astrocyte (Ca 2+ ) i is not known. We demonstrate here that 100 μM AMPA in the presence of 100 μM cyclothiazide (CTZ) causes an increase in (Ca 2+ ) i in cultured cerebral astrocytes that requires transmembrane Ca 2+ influx. This increase of (Ca 2+ ) i is blocked by 100 μM benzamil or 0.5 μM U-73122, which inhibit reverse-mode operation of the Na + /Ca 2+ exchanger by independent mechanisms. This response does not require Ca 2+ influx through VGCCs, nor does it depend upon a significant Ca 2+ influx through AMPA receptors (AMPARs). Additionally, AMPA in the presence of CTZ causes a depletion of thapsigargin-sensitive intracellular Ca 2+ stores, although depletion of these Ca 2+ stores does not decrease the peak (Ca 2+ ) i response to AMPA. We propose that activation of AMPARs in astrocytes can cause (Ca 2+ ) i to increase through the reverse mode operation of the Na + /Ca 2+ exchanger with an associated release of Ca 2+ from intracellular stores. This proposed mechanism requires neither Ca 2+ -permeant AMPARs nor the activation of VGCCs to be effective.

Journal

Brain ResearchElsevier

Published: Dec 22, 2000

References

  • Intracellular calcium rise through L-type calcium channels, as molecular mechanism for prion protein fragment 106–126-induced astroglial proliferation
    Florio, T.; Grimaldi, M.; Scorziello, A.; Salmona, M.; Bugiani, O.; Tagliavini, F.; Forloni, G.; Schettini, A.
  • Modulation of two functionally distinct Ca 2+ stores in astrocytes: role of the plasmalemmal Na/Ca exchanger
    Golovina, V.A.; Bambrick, L.L.; Yarowsky, P.J.; Krueger, B.K.; Blaustein, M.P.
  • Glutamate-induced calcium signaling in astrocytes
    Kim, W.T.; Rioult, M.G.; Cornell-Bell, A.H.
  • Glutamate-stimulated production of inositol phosphates is mediated by Ca 2+ influx in oligodendrocyte progenitors
    Liu, H.-N.; Molina-Holgado, E.; Almazan, G.
  • Glutamate-mediated astrocyte-neuron signaling
    Parpura, V.; Basarsky, T.A.; Liu, F.; Jeftinija, S.; Haydon, P.G.
  • Postsynaptic phospholipase C activity is required for the induction of homosynaptic long-term depression in rat hippocampus
    Reyes-Harde, M.; Stanton, P.K.
  • Analysis of AMPA receptor properties during postnatal development of mouse hippocampal astrocytes
    Seifert, G.; Zhou, M.; Steinhauser, C.
  • Characteristics of thrombin-induced calcium signals in rat astrocytes
    Ubl, J.J.; Reiser, G.
  • Dopaminergic modulation of excitatory postsynaptic currents in rat neostriatal neurons
    Umemiya, M.; Raymond, L.A.
  • Different characteristics of AMPA receptor agonists acting at AMPA receptors expressed in Xenopus oocytes
    Wahl, P.; Madsen, U.; Banke, T.; Krogsgaard-Larsen, P.; Schousboe, A.

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