a hypothesis that this enhancement is due to a stimulation of the glycoside binding to sarcolemmal na+ , k+-adenosine triphosphatase ( atpase ) caused by an increase in intracellular na+ available to the sodium pump was tested in isolated left atrial muscle preparations of guinea-pig heart , incubated at 30 degrees c and electrically stimulated at 0.5 , 1 or 2 hz .
C0001479
na
C0001473
atpase