Ca2+ sources for the exocytotic release of glutamate from astrocytes

►Astrocytes can exocytotically release the gliotransmitter glutamate. ►Various Ca2+ sources contribute to cytosolic Ca2+ dynamics that can drive exocytosis. ►The ER is the main source of Ca2+. ►There is also some Ca2+ entry from the extracellular space. ►Cytosolic Ca2+ levels can be modulated by mitochondria.