RESUMO
In this study, the ontogeny of the dopamine D1 and D2 receptors on fetal rat retina was investigated by using in situ hybridization technique. The expression of the D1 and D2 receptor mRNAs showed different pattern of appearance, distribution and density. At gestational day(GD) 13.5, D1 receptor was first detected in neuroepithelium of the retina. Both D1 and D2 receptors were detected at GD 15.5 in the ventricular layer and ganglion cell layer of developing retina of the rat, and D1 receptor showed more strong density than that of D2 receptor. At GD 17.5, Both D1 and D2 receptors were detected in the ganglion cell layer, ventricular layer and pigment epithelium. The labelling density of D1 receptor was higher than that of D2 receptor. At GD 19.5, both D1 and D2 receptors were additionally detected in the optic nuclear layer and plexiform layer. These results imply that D1 and D2 receptor may mediate different important function of the retina.