Dipyridamole inhibition of Ca⁺⁺-activated K⁺ fluxes compared with sickling-induced Na⁺influx.

Washed SS RBCs were suspended at 2% hematocrit and exposed to the nominal concentrations of dipyridamole indicated. Samples were then divided for separate measurement of sickling-induced Na⁺influx (▪) and (ionophore A23187) Ca⁺⁺-activated K⁺ efflux (●) as described in “Materials and methods.” Flux values were normalized to the appropriate control flux (no drug). Mean values, with SDs, are shown for experiments in 3 individuals.