Sodium-calcium exchanger modulates the L-glutamate Ca signalling in type-1 cerebellar astrocytes

We have previously demonstrated that rat type-1 cerebellar astrocytes express a very active Na/Ca exchanger which accounts for most of the total plasma membrane Ca fluxes and for the clearance of Ca induced by physiological agonist. In this chapter, we have explored the mechanism by which the reverse Na /Ca exchange is involved in agonist-induced Ca signalling in rat cerebellar astrocytes. Laser-scanning confocal microscopy experiments using immunofluorescence labelling of Na /Ca 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 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. © Springer Science+Business Media New York 2013.