A METHOD FOR THE CYTOCHEMICAL DEMONSTRATION OF SODIUM-ACTIVATED ADENOSINE TRIPHOSPHATASE

Abstract

(1) In the histochemical method for adenosine triphosphatase, when magnesium and ATP are in equivalent concentrations, and sodium is present in the medium, staining occurs in the tissues. When sodium is omitted from this medium some structures—previously stained in the presence of sodium—fail to stain. (2) Ouabain inhibits staining when magnesium and ATP are equivalent and sodium is present in the medium. (3) The effects of calcium, potassium and sodium on staining with the proposed medium parallel the effects of these ions on activity of sodium-activated ATPase in vitro. (4) When magnesium ions and ATP are not equivalent in the substrate, sodium and ouabain fail to affect staining. (5) Certain tissue structures—such as the axonic nerve ending—which have been shown to contain sodium-activated ATPase in vitro, stain in the presence of sodium when magnesium and ATP are equivalent, but fail to stain when sodium is omitted from this medium.