Supplementary Figure 4: The effects of diffusion of intracellular BAPTA in the astrocytic syncytium depend on the concentration of BAPTA used and are occluded in Ca²⁺-free aCSF.

(a) Dialysis of an astrocyte with a low concentration of BAPTA (0.1 mM) does not prevent bursting in the adjacent neuron, even after one hour (n = 4/4 pairs in 4 slices from 4 rats). (b) Spontaneous rhythmic bursting of an NVsnpr neuron recorded in Ca²⁺-free aCSF (top left) persisted after dialysis of an adjacent astrocyte (green trace) with BAPTA (20 mM, bottom left, n = 3 pairs in 3 slices from 3 rats) consistent with an astrocytic regulation of neuronal bursting by decreasing [Ca²⁺]_e.