P2RX7 and carcinoma of esophagus: As expected by the negative results of RT–PCR for the mRNA-expression of P2X1 and P2X7 receptors, no increase in [Ca2+]i was observed when the cells were challenged by the P2X-receptor agonist α,β-meATP, which additionally excluded a contribution of these receptor subtypes in the observed apoptotic and cell cycle arresting effects on oesophageal cancer cells.