because high extracellular k+ concentrations ( 18-20 mm ) increased glial na+- and k+ -dependent adenosine triphosphatase [ ( na+ + k+ ) -atpase ] activities , while this increase was not observed in neuronal preparations , it is hypothesized that k+ released in the extracellular space during neuronal firing is actively taken up by glial cells .
C0001473
adenosine triphosphatase
C0001479
na