TABLE 1

The families of P2X and P2Y receptors

The IUPHAR recommendations for nomenclature of mammalian P2Y receptors are adopted here. Additional gene products tentatively named p2y₅, p2y₇, p2y₉, and p2y₁₀ receptors display no functional responses to nucleotides. The p2y₃ receptor is the avian ortholog to the P2Y₆ receptor. The Xenopus laevis p2y₈ receptor shares high homology with the mammalian P2Y₂ and P2Y₄ receptors.