Pharmacological characterization of BNMPA (alpha-benzyl-N-methylphenethylamine), an impurity of illicit methamphetamine synthesis.

alpha-Benzyl-N-methylphenethylamine (BNMPA), an impurity of illicit methamphetamine synthesis, has previously been reported to produce convulsions in mice without affecting spontaneous locomotor activity or altering methamphetamine-induced increases in spontaneous activity. In this study the in vitro effects of BNMPA on a variety of neuronal receptor types was determined to better characterize the pharmacological actions of this novel compound. BNMPA and N-demethyl-BNMPA fully displaced the dopamine transporter selective ligand [3H]CFT (2-beta-carbomethoxy-3-beta-(4-fluorophenyl)tropane) from rat striatal membranes with Ki values (mean +/- S.E.M) of 6.05 microM +/- 0.15 and 8.73 microM +/- 1.66, respectively. BNMPA also inhibited [3H]dopamine uptake into striatal synaptosomes with an IC50 value of 5.1 +/- 1.4 microM. The basal efflux of [3H]dopamine from striatal slices was slightly enhanced by BNMPA only at concentrations > or = 100 microM. BNMPA had no effect on [3H]norepinephrine efflux from hippocampal slices. BNMPA displaced tritiated paroxetine and prazosin binding from rat cortical membranes with Ki values of 14.5 microM and 11.7 microM respectively. In electrophysiological studies, BNMPA (100 microM) had no significant effects on either GABAA Cl- currents in cultured neurons or non-NMDA glutamate receptors expressed in oocytes. However, BNMPA significantly inhibited NMDA-stimulated currents in oocytes expressing the NR1/2A or NR1/2C receptor subunit combinations (IC50 values = 24.6 +/- 1.8 and 24.0 +/- 1.5 microM, respectively). This inhibition was rapid, reversible and voltage-dependent. These results indicate that BNMPA has multiple sites of action in the CNS that could be important in modulating a variety of behavioral effects upon exposure to this synthetic byproduct of illicit methamphetamine synthesis.