to evaluate the role of the plasma membrane na : ca exchanger , 10 ( -4 ) m ouabain was added and caused a slight decline in total cell ca2+ content and no change in ionized ca2+ measured by the null-point method , suggesting that the plasmalemmal na+ : ca2+ exchanger does not play an important role in ca2+ extrusion .
C0007634
cell
C0007603
plasmalemmal