Dopamine receptors in rabbit and rat eye: characterization and localization of DA₁ and DA₂ binding sites

Abstract

In vitro autoradiography is used to characterize and localize DA₁ and DA₂ receptors in rabbit and rat eyes. The bindings of 125I-SCH 23982 (DA₁ antagonist) and of ¹²⁵I-lodosulpride (DA₂ antagonist) to slide mounted tissue sections take place with characteristics expected of substances that recognize DA₁ and DA₂ receptors respectively. They are saturable, nave high affinity and exhibit an appropriate pharmacology. The regional distribution of these receptors indicates that they are mainly present in retina. Precise cellular localizations are visualized in retinal structures by means of histoautoradiography: DA₁ receptors are found in inner plexiform layer, outer plexiform layer and inner nuclear layer and DA₂ binding sites are present in the two plexiform layers.