Abstract
The purpose of the present paper was to investigate the proliferation of rod photoreceptor cells in the retina of Japanese eel, elvers from the coastal sea, adults from the river, and migrating adults from the ocean by means of histological and immunocytochemical methods. An increase was found in the ratio between the total nuclear number in the outer nuclear layer and the number of cone cells, and an increase in the number of rod outer segment layers (including inner segments). Using proliferating cell nuclear antigen-immunocytochemistry labeled cells were observed in the outer and inner nuclear layers in adult eel from the river. These results suggest that rod photoreceptor cells proliferate in the eel retina throughout its life history.
