Representative recordings of whole-cell current measurements in oxygenated HbA cells before and after Gd³⁺ addition (50 μM). (A-B) Before Gd³⁺ addition. (C-D) At least 3 minutes after Gd³⁺ addition. Corresponding averaged data are presented in panels E and F as means ± SEM before (○) and after (▪) Gd³⁺ addition; n = 6 (E) and n = 5 (F). Measurements presented in panels A, C, and E were made using NaCl-containing bath and pipette solution; measurements presented in panels B, D, and F were made using NaCl-containing bath and Na-gluconate–containing pipette solution. The insets to panels E and F highlight indicate more clearly reversal potential following Gd³⁺ addition.