Figure 4. Characterization of P2X7R-mediated responses in U138-wt, U138-P2X7 polyclone and U138-P2X7 clone glioma cells.

P2X7R mRNA expression was determined in transfected cells by (A) RT-PCR and (B) qPCR. P2X7R protein expression level was measured by Western blot (C) and flow cytometry (D). Representative traces (E) and average (F) intracellular Ca²⁺ rise following stimulation with 200 μM BzATP. (G) Representative trace showing the effect of 10 μM A740003 on the intracellular calcium rise triggered by 200 μM BzATP. (H) Representative trace showing the effect of extracellular Ca²⁺ removal on the BzATP-triggered intracellular Ca²⁺ rise. (I) Representative trace showing 200 μM BzATP-induced ethidium bromide uptake. (J) Representative trace showing intracellular Ca²⁺ increase and (K) ethidium bromide uptake following stimulation with 200 μM BzATP. Data were analyzed by ANOVA followed by Tukey test. *Significantly different from U138-wt and ^# significantly different from the U138-P2X7 polyclone (p < 0.05). All experiments were carried out at least three times, except flow cytometry (n = 1).