Figure 4. ATP-induced [Ca²⁺]_i elevation in glioblastoma cells originates primarily from thapsigargin-sensitive intracellular Ca²⁺ stores.

A, a single fura-2 AM-loaded glioma cell was stimulated with 100 μM ATP in standard bath solution (left trace) and after 2 min incubation in Ca²⁺-free extracellular medium (right trace). B, mean response of twenty-nine glioma cells to ATP in standard bath solution and after cell treatment with 100 nM TG. The inset shows that TG did not affect the membrane potential of the glioblastoma cell.