Nematosomes in external horizontal cells of white perch (Roccus americana) retina: changes during dark and light adaptation.

ABSTRACT

Cytoplasmic inclusions resembling nucleoli and termed nematosomes have been described in several areas of the nervous system but not in the retina. Here we report the presence of these structures in the external horizontal cells of white perch (Roccus americana). Nematosomes were larger and more numerous in dark-adapted retinas than in light-adapted ones. An inverse relation of horizontal cell spinules was found in these cells, suggesting that electron-dense material observed in spinules may originate from nematosomes.