In this current study, using a glaucoma animal model, we have analyzed the expression levels of three P2Y metabotropic receptors (P2Y1, P2Y2, and P2Y6), which are known to be activated by Ap4A (Guzman-Aranguez et al., 2007), in the ciliary body and iris of control (C57BL/6) and glaucomatous (DBA/2J) mice. This evidence concerns the gene P2RY2 and glaucoma.