Cytochemical study of the electron microscopic localization of potassium dependent p nitrophenyl phosphatase activity in choroidal ependymal epithelium in normal rat brain comparing with the activity of magnesium atpase and alkaline phosphatase
Masuzawa, T.; Saito, T.; Sato, F.
Acta Histochemica et Cytochemica 13(4): 394-403
To determine the ultracytochemical localization of Na+,K+-ATPase activity in normal rat choroidal epithelium, K+ dependent-p-nitrophenylphosphatase activity was studied by using the 1-step lead citrate method devised by Mayahara et al. An electron dense reaction product was abundant inside the microvilli and positively along the outside of the basal plasmalemmas of the choroidal epithelium. No reaction product was seen on the apical and lateral ones. In the cytoplasm, the electron dense precipitates were also observed in the endoplasmic reticulum and nuclear membrane. Ouabain (10-3-10-4 M) effectively inhibited the activities in the microvilli and basal plasmalemmas. Alkaline phosphatase reaction stronger than that of Mg2+-ATPase was observed mainly on the outside of the basal plasmalemmas, but the activities of these 2 enzymes were not found in the microvilli.