Together with the functional role of P2X1R in Up4A-mediated vasoconstriction in perfused rat/mouse kidney [5, 12] and isolated mouse aortas [8], this evidence suggests that there is likely a similar activation of P2X1R in Up4A-induced decreases in CF in WT mice as compared to ApoE KO mice. This evidence concerns the gene APOE and cystic fibrosis.