Neural cell adhesion molecule (NCAM) in adult vertebrate retinas: tissue localization and evidence against its role in retina-pigment epithelium adhesion

The presence of neural cell adhesion molecule (NCAM) was examined in the neural retina, interphotoreceptor matrix (IPM), and retinal pigment epithelium (RPE) of adult bovine and frog eyes. Using polyclonal antibodies raised against adult isoforms of NCAM. Western blot analyses revealed the presence of NCAM in the neural retina, but not in the IPM or RPE of these species. As a control, Western blot analysis was used to demonstrate the presence of interphotoreceptor retinoid-binding protein (IRBP) in the IPM preparations. NCAM immunoreactivity was detected by light microscopic immunocytochemistry primarily in the plexiform layers and nerve fibre layer of the frog retina. Minor immunoreactivity was also detected in the inner and outer nuclear layers, but there was no detectable NCAM immunoreactivity in the IPM, outer segments, or RPE. These results indicate that NCAM is not a likely participant in the process of retina-RPE adhesion in the adult eye.