Figure 5. Activation of capacitative Ca²⁺ entry in glioblastoma cells.

A, a single cell was stimulated by 100 μM ATP in standard bath solution and in Ca²⁺-free extracellular medium. Restoration of extracellular Ca²⁺ caused a [Ca²⁺]_i transient which slowly returned to baseline. B, mean response of fifty-one cells to a long-lasting ATP application. ATP triggered an initial peak which was followed by a plateau phase. Removal of extracellular Ca²⁺ eliminated the plateau phase; after restoration of Ca²⁺ into the extracellular medium complete recovery of the plateau was observed.