FIGURE 5.

Gentamicin and hemichannel blockers reduce the ATP-evoked Ca²⁺ signal in HeLa-rCx26GFP cells. HeLa-Parental cells or HeLa cells stably transfected with rCx26-GFP were loaded with Fura-2 and then stimulated with bath application of 10 μM ATP. (A) Time course of ATP-evoked intracellular Ca²⁺ signal under control conditions in HeLa-Parental cells. (B) Time course of ATP-evoked intracellular Ca²⁺ signal in HeLa-Parental cells pre-incubated for 5 min with 200 μM gentamicin. Five representative cells are shown in each case. (C) Time course of ATP-evoked intracellular Ca²⁺ signal under control conditions in HeLa-rC26-GFP cells. (D) Time course of ATP-evoked intracellular Ca²⁺ signal in HeLa-rC26-GFP cells pre-incubated for 5 min with 200 μM gentamicin. (E) Compiled data showing the amplitude of Ca²⁺ signal changes evoked by extracellular ATP (mean ± SEM) in HeLa parental and HeLa-rCx26GFP, measured as area under curve expressed as AU in control conditions or after 5 min preincubation with 200 μM gentamicin, 10 min with 100 μM carbenoxolone (CBX) or 20 min with 200 μM GAP-26. (F) Duration (time), from the first Ca²⁺ signal increase until the return to baseline (mean ± SEM) in HeLa-Parental and HeLa-rCx26GFP in control conditions or after 5 min preincubation with 200 μM gentamicin, 10 min with 100 μM CBX or 20 min with 200 μM GAP-26. For calculations of the average traces (as shown in A) 40 cells per experiment were included. The number of independent experiments is indicated in each bar. **P < 0.01, ***P < 0.001.