Figure 4.

CK enhances the sustained calcium response associated with hP2X7 receptor activation. (A) Intracellular Ca²⁺ responses were measured in fluo-4AM loaded HEK-hP2X7 cells or untransfected HEK-293 cells. Baseline values were recorded for 15 s and then ATP was applied. Increasing concentrations of ATP (100 , 200 and 500 μM) allow a sustained Ca²⁺ response to be measured in P2X7-expressing cells. (B) HEK-hP2X7 or untransfected HEK cells were treated with 100 μM ATP, 100 μM ATP + 0.1% DMSO or 100 μM ATP + 10 μM CK and fluo-4 responses measured over time. (C) Quantitative measures of peak Ca²⁺ response (maximum–baseline) and sustained Ca²⁺ response (mean fluorescence between 140 and 300 s) in both HEK-hP2X7 and HEK cells. **P < 0.05, significant effect of CK; one-way anova with Dunnett's post-test.