In ARPKD and ADPKD model mice, the protein expression level of the P2X7 receptor was significantly elevated in cystic epithelial cells.[46,47] Pannexin-1 (PANX-1), an ion channel capable of releasing ATP, is also significantly more expressed in cystic epithelial cells than in normal tubular epithelial cells. This evidence concerns the gene P2RX7 and autosomal recessive polycystic kidney disease.