ADRB3 and retinal disorder: It is acknowledged that this receptor is up-regulated by the hypoxic microenvironment, as occurs in the developing embryo during intra-uterine life [15,16,17] or during the hypoxic phase of retinopathy [32], but, to the best of our knowledge, little is known about the effect of hyperoxia on β3-AR expression, with the only relevant information being our recent report showing its downregulation on the murine ductus arteriosus after delivery when newborns are exposed to a more oxygenated environment as compared with that occurring in utero [18].