Fig. 1.

a, concentration-dependent inhibition of endogenous adenosine uptake by NBMPR in vector-transfected MDCK cells. Cells were incubated at 37°C with [³H]adenosine (1 μM) for 2 min in the presence of NBMPR at the indicated concentrations. b, concentration-dependent inhibition of PMAT-mediated MPP⁺ uptake by classic nucleoside transport inhibitors. PMAT-expressing and vector-transfected MDCK cells were incubated at 37°C with 0.1 μM [³H]MPP⁺ for 1 min in the presence of inhibitors at indicated concentrations. Each data point represents PMAT-specific uptake, calculated by subtracting the uptake in vector-transfected cells at various inhibitor concentrations from the corresponding uptake in PMAT-expressing cells. Each value represents the mean ± S.D. (n = 3).