TABLE 2

Inhibition of [3H]-l-carnitine uptake in BeWo cells by amphetamine analogs

Uptake of 10 nM [3H]-l-carnitine in BeWo cells was determined at 37°C for 30 min in the presence or absence (control) of the amphetamine derivatives listed. The assignments for substituents R1, R2, and R3 correspond to the template structure shown in Fig. 6. Data were corrected for protein content and expressed as percentages of the control uptake. IC50 values for each inhibitor were obtained by fitting the data as described in the text. The error represents the standard deviation from three or four IC50 determinations. The compounds are listed in order of increasing IC50 values.

Compound
R1
R2
R3
IC50
mM
(+)-Methamphetamine H H CH3 2.3 ± 0.5
(+)-Ephedrine H OH CH3 2.7 ± 1.3
(+)-ψ-Ephedrine OH H CH3 4.2 ± 0.7
(-)-Chloroephedrine H Cl CH3 4.8 ± 0.5
(+)-Chloroephedrine Cl H CH3 5.0 ± 2.6
(+)-Amphetamine H H H 6.0 ± 1.0
(-)-Norephedrine H OH H 7.1 ± 3.8
(+)-Nor-ψ-ephedrine
OH
H
H
9.2 ± 3.9