“…An alteration in purinergic receptor subtype expression patterns has been observed in diabetes in the retina and other tissues (Ho et al, ; Kneer, Green, Meyer, Rich, & Minns, ; Mankus, Rich, Minns, & Trinkaus‐randall, ; Seref‐ferlengez, Maung, Schaffler, & Spray, ; Vindeirinho, Santiago, Cavadas, Ambrósio, & Santos, ). For example, in diabetic animals, an increase in levels of P2X 7 R has been reported in corneal epithelium (Kneer et al, ; Mankus et al, ), although a decrease in the expression of these receptors also was shown in osteocytes under HG conditions (Seref‐ferlengez et al, ). Likewise, the metabotropic receptors P2Y 2 R and P2Y 4 R suffer an overexpression in osteoblasts under diabetic conditions (Seref‐ferlengez et al, ), as do some adenosine receptors in the retina (Vindeirinho, Costa, Correia, & Santos, ).…”