Sodium localition in the adult brain. I. Normal brain tissue.

Abstract

Grossly visible precipitates were formed when 2% solution of potassium pyroantimonate was added to 0.01 M acetic acid, 0.1 N hydrochloric acid, or some divalent cation solutions. Localization of sodium ion in the brain of rat and cat was, therefore, studied by use of potassium pyroantimonate buffered with s-collidin. The sodium precipitates were observed mainly on the plasma membranes of neuron, astrocyte, endothelial and perivascular cells as well as erythrocyte. In the neuron, the precipitates were most numerous on the plasma membranes of terminal boutons and dendrites, particularly synapses. The dense precipitates were less in number on the plasma membranes of astrocyte, endothelial and perivascular cells than of neuron. In addition, there was some evidence of the dense precipitates localized in the extracellular space. All of the sodium precipitates shown on the plasma membranes in the brain were situated on the internal surface of the plasma membranes. Similar localization of the sodium ion was evident on the plasma membrane of the erythrocyte. The site of the sodium precipitates on the plasma membranes was discussed in relation to the distribution of Na+-K+ stimulated ATPase.