Tetraethylammonium (TEA) transport across porcine renal proximal tubular cell (LLC-PK1) monolayers. The transport (basolateral-to-apical) of TEA was assessed in LLC-PK1 cells monolayers. Cell monolayers were exposed to [ethyl-1-14C] TEA (5 μM) in the presence or absence of quinidine (1E+03 μM) for 60 minutes. The transport of TEA was assessed by measuring the appearance of [ethyl-1-14C] TEA radioactivity in the apical compartment at specific time intervals (0, 15, 30, 45 and 60 minutes) for 60 minutes. Radioactivity was measured as disintegrations per minute (DPM). The TEA transport is expressed as the concentration of [ethyl-1-14C] TEA in the apical compartment. Results are presented as the mean (±standard error (SE)) from 3 cell monolayer experiments. * p < 0.05, compared to [ethyl-1-14C] TEA radioactivity in the apical compartment in the absence of quinidine.