Retinal pigment epithelium contains a distinctive strychnine-binding site

Membranes prepared from the retinal pigment epithelium of several species possess a specific site which binds [3H]strychnine. This binding has a somewhat lower affinity and a much greater density than the corresponding interaction in the hindbrain or neural retina. Binding is not greatly altered in the presence of 10(-3) M glycine, L-alanine, beta-alanine, taurine, or serine. Thus, the receptor does not resemble the classical glycine receptor of the hindbrain and spinal cord. This new type of binding site appears to be confined to the pigment epithelial layer of the retina.