Beta adrenergic binding sites in the human eye: an autoradiographic study

Beta adrenergic binding sites were localized and characterized in the human eye by means of "in vitro" autoradiography, using [125I] (-) iodocyanopindolol (125ICYP) as radioligand. Binding sites were visualized by apposition of isotope sensitive film to slide mounted eye sections. Receptor sites were present in the extraocular muscles, in the conjunctiva, in the epithelium and endothelium of the cornea, in the trabeculum and in the ciliary muscle. They were also present in the lens epithelium and in the retina. The pigmented ocular structures were heavily labelled but the binding was nonspecific. Characterization of these binding sites was achieved by testing the ability of selective adrenergic compounds to displace 125ICYP binding. These studies suggested that the majority of adrenergic binding sites in nonpigmented structures of human eye were of a beta2 type.