ANTI-ARRESTIN IMMUNOREACTIVITY IN THE HUMAN RETINA - DIFFERENCE BETWEEN LIGHT-ADAPTATION AND DARK-ADAPTATION

Differences in arrestin (Arr) immunolocalization between light(LA)- an d dark(DA)- adapted retinae have been described in various species. We have for the first time studied 5 LA and 5 DA human retinae from surg ically enucleated eyes, each group comprising 1 exenteration specimen and globes with malignant melanoma or 2 degrees glaucoma. To examine t he distribution of An; immunohistochemistry was performed on paraffin sections using three different antibodies to Arr: a48k, 3D1.2, and 5c6 .47. Immunoreactivity (IR) was tested using the avidin-biotin method, and results were visualized with diaminobenzidine. With both a48k and 596.47, labeling was most intense in the photoreceptor layer. When com paring LA and DA retinae, IR of photoreceptor outer segments (OS) was clearly different with very little IR in OS of DA but distinct positiv ity in OS of LA retina. This was most obvious in melanoma eyes where r etinal morphology was well-preserved while in glaucomatous eyes with r etinal degeneration this pattern was less apparent. 3D1.2 did not reac t in any of the specimens. Although there was some variation within ea ch group, we demonstrated a distinct difference in anti-Arr IR between LA and DA specimens. Thus Arr-IR might now be used as a promising too l to further study retinal diseases on human surgical specimens involv ing photoreceptor degeneration.