Table 1

Inhibition constants for organic cations to compete with the [14C]tetraethylammonium accumulation by MDCK-OCT1 and MDCK-OCT2 cells

CompoundsKi Values for Tetraethylammonium Accumulation
OCT1 (μM)OCT2 (μM)
1-Methyl-4-phenylpyridinium0.81.8
Cimetidine5.79.4
Quinidine14.619.1
Tetraethylammonium46.652.2
Nicotine64.350.5
N1-Methylnicotinamide669.2403.4
Guanidine724.2713.6