Figure 2.

The chromatographic traces from the frontal competitive displacement chromatography of 10 pM [³H]-N-methyl 4-phenyl pyridinium ([³H]-MPP⁺), where: trace A (MPP⁺) was obtained with [³H]-MPP⁺ alone; trace B (MPP⁺ and (R,R)-fenoterol) was obtained after the addition of 10 μM (R,R)-fenoterol to the mobile phase; trace C (MPP⁺ and (S,S)-fenoterol) was obtained after the addition of 10 μM (S,S)-fenoterol to the mobile phase. The experiments were carried out using a stationary phase containing immobilized membranes obtained from the hOCT1-MDCK cell line, the hOCT(+)-IAM column, see text for experimental details. hOCT1, human organic cation transporter-1; IAM, immobilized artificial membrane.