Ultrastructural localization of ouabain-sensitive potassium-dependent p-nitrophenylphosphatase (NA+-K+-ATPase) activity in the central nervous system of the rat.

A new one-step ultracytochemical method for the detection of ouabain-sensitive, potassium-dependent p-nitrophenylphosphatase (K+-NPPase) activity of the Na+-K+-ATPase complex was developed by Mayahara et al. (7, 8). We have now applied this method to the central nervous system of the rat. K+-NPPase activity was most intense over the entire plasma membrane of the synaptic area. Reaction products showing K+-NPPase activity were also precipitated on the axolemma, dendritic plasma membrane and filamentous structures in the axon and dendrite. No significant activity was found on the glial plasma membrane.