A new approach to inhibiting astrocytic IP₃-induced intracellular calcium increase in an astrocyte-neuron co-culture system

Astrocytes exhibit dynamic Ca²⁺ mobilization, such as Ca ²⁺ wave and Ca²⁺ oscillation, via an inositol 1,4,5-triphosphate-induced Ca²⁺ release (IICR)-dependent mechanism. The physiological functions of astrocytic Ca²⁺ 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 Ca²⁺ 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 Ca²⁺ signaling on neuronal function.