Table 1

Effect of pH, unlabeled TEA, and quinidine on efflux of [14C]TEA from OCTN1-transfected HEK293 cells

External pH20 s3 min5 min
6.0 (Control)54.0  ± 4.8845.3  ± 1.2736.3  ± 0.50
6.660.1  ± 1.6349.3  ± 1.8737.7  ± 0.27a
7.464.3  ± 2.8159.1  ± 1.61a 51.3  ± 1.32a
8.067.9  ± 0.93a 69.2  ± 1.15a 61.8  ± 2.00a
6.0 + TEA55.5  ± 1.9435.5  ± 1.30b 28.1  ± 0.77b
6.0 + Quinidine63.2  ± 1.2863.1  ± 1.70a 58.2  ± 0.96a

Efflux of [14C]TEA was measured after preloading OCTN1-expressed HEK293 cells with [14C]TEA (150 μM) for 10 min. Each value represents mean ± S.E. of three or four determinations, and results were shown as percentage of remaining amount of initial [14C]TEA in cells at indicated efflux time. Concentration of unlabeled TEA and quinidine in efflux medium was 1 mM.

  • a,b Significantly higher (a) or lower (b) than value of control at each time point (p< .05).