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. Here, PANX1 is linked to autosomal recessive polycystic kidney disease.