Cytochemical localization of ouabain-sensitive, K+-dependent p-nitro-phenylphosphatase (transport ATPase) in the mouse central and peripheral nervous systems.

Enzyme activity, representing the sites of K+-dependent p-nitrophenylphosphatase (K+-pNPPase), a component of the transport adenosine triphosphatase (Na+,K+-ATPase) system, has been localized at the ultrastructural in both cerebral cortex and in sciatic nerve of the mouse. Normal mice and animals with mechanically injured blood-brain barrier (BBB) were used. In the cerebral cortex, positive reaction was found in synapses, plasmalemma of neurites (axons and dendrites), in endothelial cell of microblood vessels and in the plasmalemma of mesothelial cells of the pia mater. In the sciatic nerve, a strong reaction was present in the nodes of Ranvier, with weaker reaction in the internodal areas of the axolemma. In the endothelial cells of normal blood vessels, the reaction product was localized on the luminal and abluminal, or only on the abluminal plasmalemma. After damage of BBB, numerous invaginations, pits and pinocytic vesicles showing positive reaction in their limiting membrane appeared in the endothelial cells.