K_I = binding affinity; K_m = Michaelis constant; V_max = maximum velocity.

Data are for cloned human norepinephrine transporter stably expressed in rat C6-glial cells. Using tritium-labeled compounds, 7 different unlabeled substrate concentrations were added; 3 compounds are reported here. Cellular uptake was analyzed by Michaelis–Menten equations. C6-human NET membrane was used for binding assays. For competitive binding assays, percentage of specific binding vs. inhibitor concentration data was fitted to one-site competition model. K_I values were calculated from estimated inhibition concentration of 50% (IC₅₀) using Cheng–Prusoff correction, K_I = IC₅₀/(1 + L*/KD), where L* is ³H-mazindol concentration used, and KD was set to mean value from control saturation assays (1.20 nM). Units are μL/min/mg of protein for these in vitro studies. Final 2 rows are neuronal uptake rates that are measures of V_max/K_m from isolated rat heart studies and not C6-hNET in vitro studies. Units are mL/min/g of wet weight for these studies.