Cytochemical studies of transitional area between retina and optic nerve

We have investigated the fine structural features of the transitional area between retina and optic nerve with special emphasis on the identification of Müller cells using the cytochemical method for detecting the localization of G6Pase activity, which is specific to the endoplasmic reticulum (ER) of Müller cells in the guinea pig retina. This cytochemical method enabled us to differentiate Müller cells from astrocytes or other cells easily and also allowed topographical, three dimensional analysis by high voltage electron microscopy because of the high contrast of the reaction products. Our study demonstrates that Müller cells are a major constitutional element of intermediary tissue of Kuhnt, which is considered to be the possible site of barrier between optic nerve and retina. These findings may indicate that Müller cells contribute to the barrier function in this region of the eye.