Fig. 1. Na influx in washed red blood cells (RBCs) equilibrated to a range of oxygen partial pressure (P_O2) values in the presence of 10^–4 mol l^-1 ouabain. The influx was measured in unstimulated cells to get basal influx () and in cells stimulated by a calculated 25% osmotic shrinkage alone () or in the presence of 10^–4 mol l^-1 EIPA (•). The cell suspensions were exposed to the experimental gas mixture 10 min before shrinkage (time zero in the figures). (A) 5–15 min, (B) 15–30 min, (C) 30–45 min and (D) 45–60 min. ^* indicates statistical difference from basal influx within the same P_O2 and time interval; indicates statistical difference from air-equilibrated RBCs within the same treatment and time interval; indicates statistical difference from the same treatment and P_O2 level in the 5–15 min time interval. N=4, P<0.05.