Pharmacological Characterization of Ecstasy Synthesis Byproducts with Recombinant Human Monoamine Transporters

Abstract

Ecstasy samples often contain byproducts of the illegal, uncontrolled synthesis of N-methyl-3,4-methylenedioxy-amphetamine or 3,4-methylenedioxy-methamphetamine (MDMA). MDMA and eight chemically defined byproducts of MDMA synthesis were investigated for their interaction with the primary sites of action of MDMA, namely the human plasmalemmal monamine transporters for norepinephrine, serotonin, and dopamine [(norepinephrine transporter (NET), serotonin transporter (SERT), and dopamine transporter (DAT)]. SK-N-MC neuroblastoma and human embryonic kidney cells stably transfected with the transporter cDNA were used for uptake and release experiments. Two of the eight compounds, 1,3-bis (3,4-methylenedioxyphenyl)-2-propanamine (12) and N-formyl-1,3-bis (3,4-methylenedioxyphenyl)-prop-2-yl-amine (13) had uptake inhibitory potencies with IC 50 values in the low micromolar range similar to MDMA. Compounds with nitro instead of amino groups and a phenylethenyl instead of a phenylethyl structure or a formamide or acetamide modification had IC 50 values beyond 100 M. MDMA, 12, and 13 were examined for induction of carrier-mediated release by superfusion of transporter expressing cells preloaded with the metabolically inert transporter substrate [3 H]1-methyl-4-phenylpyridinium. MDMA induced release mediated by NET, SERT, or DAT with EC 50 values of 0.64, 1.12, and 3.24 M, respectively. 12 weakly released from NET-and SERT-expressing cells with maximum effects less than one-tenth of that of MDMA and did not release from DAT cells. 13 had no releasing activity. 12 and 13 inhibited release induced by MDMA, and the concentration dependence of this effect correlated with their uptake inhibitory potency at the various transporters. These results do not support a neurotoxic potential of the examined ecstasy synthesis byproducts and provide interesting structure-activity relationships on the transporters.

Comparative potencies of 3,4‐methylenedioxymethamphetamine (MDMA) analogues as inhibitors of [3H]noradrenaline and [3H]5‐HT transport in mammalian cell lines

“…MBDB and BDB were notably less potent than MDMA at inhibiting [ 3 H]NA uptake via NET, yet both are very effective inhibitors of 5-HT uptake at SERT, where they share a very similar inhibitory profile to that seen with MDMA. These results support the findings of Pifl et al (2005), which showed that replacement of the a-methyl group with a 3,4-methylenedioxybenzyl group greatly inhibited inhibitory potency at NET, but not SERT. MBDB has recently been listed as a controlled substance in the United States and France due to its highly addictive and unique empathogenic properties and its abuse has been noted throughout Europe and the United States (Nagai et al, 2002).…”

“…MDMA is a known substrate and an inhibitor of the 5-HT transporter (SERT), noradrenaline transporter (NET) and dopamine transporter (DAT; Verrico et al, 2005). Once inside the cell, MDMA causes the release of endogenous neurotransmitter back into the extracellular space, again via the monoamine transporters, resulting in a substantial rise in the level of extracellular neurotransmitter (Green et al, 2003;Pifl et al, 2005). Although amphetamine-induced neurotransmitter release is thought to be key in the manifestation of the neurotoxic effects of MDMA (Rothman et al, 2001;Green et al, 2003), the exact molecular mechanism by which this release occurs has yet to be determined (Siedel et al, 2005;Sulzer et al, 2005).…”

“…In light of the central role of monoamine transporters in mediating the pharmacological actions of MDMA, it was decided to investigate the effects of the MDMA analogues on NET and SERT transport in vitro, using two separate mammalian cell lines. Although the significance of DAT in mediating both the physiological and potentially toxicological effects of MDMA should not be underestimated (Colado et al, 2004;Breier et al, 2006;Rothman and Baumann, 2006), MDMA has typically demonstrated a greater inhibitory potency at NET and SERT compared to DAT in vitro (Rothman and Baumann, 2003;Pifl et al, 2005;Verrico et al, 2005). Consequently, it was decided to perform this investigation using NET and SERT.…”

Synthesis and serotonin transporter activity of 1,3-bis(aryl)-2-nitro-1-propenes as a new class of anticancer agents

“…Interestingly derivatives 5b, 4b, 7b and 6b have been previously reported as synthetic byproducts of clandestine MDMA synthesis 21 and when investigated for interaction with human monoamine transporters were found to interact with SERT at a similar potency to MDMA without displaying any neurotoxic effects (carrier-mediated release experiments) 21 . In this study we report that the 1,3-bis(3,4-methylenedioxyphenyl)-2-propamine (5b) and the 1, We conclude that the majority of these 1,3-bis(aryl)-2-propanamines have significant cytotoxic effects against the BL cell line DG-75 and the neuroblastoma cell line SHSY-5Y.…”

“…Compounds 5b, 6b and 7b have been previously identified by Bohn et al (1993) as impurities arising from the synthesis of MDA from 3,4-methylenedioxyphenylacetic acid by the Leuckart route 17 . In this study these compounds were synthesized as previously reported by Pifl et al (2005) 21 . We have previously reported the synthesis of compounds 4a, 5a, 6a, 7a, 10a, 11a, 12a and 13a, 15a 13 and they have been included in Scheme 1 for clarity.…”