Effect of NS1652 on deoxygenation-induced cation fluxes.

Normal or sickle erythrocytes were suspended (hematocrit = 10%) in an oxygenated, buffered, ouabain-containing (0.1 mmol/L) salt solution for 105 minutes before deoxygenation was initiated by application of a humid stream of argon. Upper panel: The effects of deoxygenation and NS1652 (10 μM) on the net K⁺ efflux from sickle (S/S) erythrocytes. Middle panel. Similar experiment as in (A) except with normal (A/A) erythrocytes. The extracellular K⁺concentration (Y-axis, upper and middle panel) was followed as a function of time (X-axis) by flame photometry on samples of the extracellular solution taken every 15 minutes. Control (▪) as well as NS1652-containing suspensions (⧫) were run in parallel. The broken line (middle panel) is the linear regression curve to the data obtained with the normal cells. This line has been superimposed on the data from sickle cells (upper panel). Lower panel: Net potassium effluxes per liter cells per hour, calculated by linear regression to the data points in the linear phases (0-105 minutes for oxygenized cells, 135-240 minutes for deoxygenized cells) of efflux experiments as shown in the panels above. Text boxes indicate the number of experiments; error bars indicate SD.