title: Sodium-calcium exchanger modulates the L-glutamate Ca(i) (2+) signalling in type-1 cerebellar astrocytes.
abstract: We have previously demonstrated that rat type-1 cerebellar astrocytes express a very active Na(+)/Ca(2+) exchanger which accounts for most of the total plasma membrane Ca(2+) fluxes and for the clearance of Ca                   (i)                             (2+)                  induced by physiological agonist. In this chapter, we have explored the mechanism by which the reverse Na(+)/Ca(2+) exchange is involved in agonist-induced Ca(2+) signalling in rat cerebellar astrocytes. Laser-scanning confocal microscopy experiments using immunofluorescence labelling of Na(+)/Ca(2+) exchanger and RyRs demonstrated that they are highly co-localized. The most important finding presented in this chapter is that L-glutamate activates the reverse mode of the Na(+)/Ca(2+) exchange by inducing a Na(+) entry through the electrogenic Na(+)-glutamate co-transporter and not through the ionophoric L-glutamate receptors as confirmed by pharmacological experiments with specific blockers of ionophoric L-glutamate receptors, electrogenic glutamate transporters and the Na/Ca exchange.
authors.affiliation: Laboratorio de Fisiología Celular, Centro de Biofísica, Instituto Venezolano de Investigaciones Científicas, Caracas, Venezuela.
authors.forename: Héctor
authors.initials: H
authors.lastname: Rojas
authors.forename: Claudia
authors.initials: C
authors.lastname: Colina
authors.forename: Magaly
authors.initials: M
authors.lastname: Ramos
authors.forename: Gustavo
authors.initials: G
authors.lastname: Benaim
authors.forename: Erica
authors.initials: E
authors.lastname: Jaffe
authors.forename: Carlo
authors.initials: C
authors.lastname: Caputo
authors.forename: Reinaldo
authors.initials: R
authors.lastname: Di Polo
mesh_terms: D000818:Animals; D001253:Astrocytes / Q000166:cytology / Q000378:metabolism*; D002118:Calcium / Q000378:metabolism; D020013:Calcium Signaling / Q000502:physiology*; D002531:Cerebellum / Q000166:cytology / Q000378:metabolism*; D018698:Glutamic Acid / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D009419:Nerve Tissue Proteins / Q000235:genetics / Q000378:metabolism*; D051381:Rats; D019837:Ryanodine Receptor Calcium Release Channel / Q000235:genetics / Q000378:metabolism*; D012964:Sodium / Q000378:metabolism; D019831:Sodium-Calcium Exchanger / Q000235:genetics / Q000378:metabolism*
chemical_list: D009419:Nerve Tissue Proteins; D019837:Ryanodine Receptor Calcium Release Channel; D019831:Sodium-Calcium Exchanger; D018698:Glutamic Acid; D012964:Sodium; D002118:Calcium