Figure 3.

Inhibition by compound DMPBI of specific MPP⁺ uptake into 293 cells expressing EMTr or EMTh in (a) standard buffer or (b) high potassium buffer. In K⁺ buffer, all Na⁺ ions were replaced by K⁺ to depolarize and clamp membrane potential. For both conditions, cells were preincubated without inhibitor in the respective uptake buffers for 24 min. For EMTr, control uptake in K⁺ buffer was 44% of uptake in Na⁺ buffer, and non-specific uptake amounted to 5% of total uptake in Na⁺ buffer and 7% in K⁺ buffer. For further details see legend to Figure 2.