Astrocytes play key roles in the central nervous system and regulate local blood flow and synaptic transmission via intracellular calcium (Ca 2+ ) signaling. Astrocytic Ca 2+ signals are generated by multiple pathways: Ca 2+ release from the endoplasmic reticulum (ER) via the inositol 1, 4, 5-trisphosphate receptor (IP 3 R) and Ca 2+ influx through various Ca 2+ channels on the plasma membrane. However, the Ca 2+ channels involved in astrocytic Ca 2+ homeostasis or signaling have not been fully characterized. Here, we demonstrate that spontaneous astrocytic Ca 2+ transients in cultured hippocampal astrocytes were induced by cooperation between the Ca 2+ release from the ER and the Ca 2+ influx through store-operated calcium channels (SOCCs) on the plasma membrane. Ca 2+ imaging with plasma membrane targeted GCaMP6f revealed that spontaneous astroglial Ca 2+ transients were impaired by pharmacological blockade of not only Ca 2+ release through IP 3 Rs, but also Ca 2+ influx through SOCCs. Loss of SOCC activity resulted in the depletion of ER Ca 2+ , suggesting that SOCCs are activated without store depletion in hippocampal astrocytes. Our findings indicate that sustained SOCC activity, together with that of the sarco-endoplasmic reticulum Ca 2+ -ATPase, contribute to the maintenance of astrocytic Ca 2+ store levels, ultimately enabling astrocytic Ca 2+ signaling. [ABSTRACT FROM AUTHOR]