LIGHT AND ELECTRON-MICROSCOPIC DEMONSTRATION OF THE OUABAIN-SENSITIVE, POTASSIUM-DEPENDENT P-NITROPHENYLPHOSPHATASE ACTIVITY (K-NPPASE) USING A CE-MG-DOUBLE CAPTURE TECHNIQUE

The cerium-based method of Kobayashi et al. for the histochemical demo nstration of K-NPPase activity was improved. Besides Ce3+ additionally Mg2+ ions as orthophosphate capture were employed (double capture tec hnique). For light microscopical purposes the Mg-phosphate was convert ed into Ce-phosphate by treatment of the sections with Ce-citrate yiel ding higher quantity of reaction product. Unspecific background staini ng was eliminated by EGTA. In the electron microscope this technique b rought about fine granular reaction products without diffusion artefac ts.