Astrocytes exhibit dynamic Ca 2+ mobilization, such as Ca 2+ wave and Ca 2+ oscillation, via an inositol 1,4,5-triphosphate-induced Ca 2+ release (IICR)-dependent mechanism. The physiological functions of astrocytic Ca 2+ mobilization, however, are poorly understood. To investigate this issue, we created a plasmid encoding an enhanced green fluorescent protein-tagged inositol 1,4,5-triphosphate absorbent protein and expressed it in cultured astrocytes. Expression of this protein inhibited both IICR and the Ca 2+ wave in cultured astrocytes. By combining this method to the single cell electroporation technique, we were able to inhibit IICR specifically in astrocytes in an astrocyte–neuron co-culture system. Our approach provides a useful tool for direct examination of the physiological role of astrocytic Ca 2+ signaling on neuronal function.