Neurons and astroglia express distinct subsets of Na,K-ATPase α and β subunits

We have analyzed the expression pattern of Na,K-ATPase α and β subunit isoforms within the rodent and primate central nervous system. Membrane fractions prepared from rat cerebral cortical type-1 astrocytes and rat cerebellar granule and hippocampal neurons were characterized by immunoblot analyses using a panel of α and β subunit isoform-specific antisera. Each cell type was found to express the α1 isoform but showed differences in the expression of other subunits. Cortical astrocytes displayed α2 and β2 subunits, whereas cerebellar granule neurons showed expression of α3 and β1 subunits. All three α subunit isotypes were detected in hippocampal neurons. A survey of the immunofluorescent staining pattern of the α3 subunit in rat and monkey brain confirmed that expression of this Na,K-ATPase α subunit isoform was restricted exclusively to neurons. These results suggest that both neurons and astrocytes express multiple, yet distinct, Na,K-ATPase isoenzymes. The identification of cell types expressing limited combinations of α and β subunits should provide a framework for understanding the physiological significance of Na,K-ATPase isoenzyme diversity and may provide useful tools for the analysis of cell lineage in the mammalian central nervous system.