"Ecstasy"-induced toxicity in SH-SY5Y differentiated cells: role of hyperthermia and metabolites

Abstract

3,4-Methylenedioxymethamphetamine (MDMA; "ecstasy") is a recreational hallucinogenic drug of abuse known to elicit neurotoxic properties. Hepatic formation of neurotoxic metabolites is thought to play a major role in MDMA-related neurotoxicity, though the mechanisms involved are still unclear. Here, we studied the neurotoxicity mechanisms and stability of MDMA and 6 of its major human metabolites, namely α-methyldopamine (α-MeDA) and N-methyl-α-methyldopamine (N-Me-α-MeDA) and their correspondent glutathione (GSH) and N-acetyl-cysteine (NAC) conjugates, under normothermic (37 °C) or hyperthermic conditions (40 °C), using cultured SH-SY5Y differentiated cells. We showed that MDMA metabolites exhibited toxicity to SH-SY5Y differentiated cells, being the GSH and NAC conjugates more toxic than their catecholic precursors and MDMA. Furthermore, whereas the toxicity of the catechol metabolites was potentiated by hyperthermia, NAC-conjugated metabolites revealed higher toxicity under normothermia and GSH-conjugated metabolites-induced toxicity was temperature-independent. Moreover, a time-dependent decrease in extracellular concentration of MDMA metabolites was observed, which was potentiated by hyperthermia. The antioxidant NAC significantly protected against the neurotoxic effects of MDMA metabolites. MDMA metabolites increased intracellular glutathione levels, though depletion in thiol content was observed in MDMA-exposed cells. Finally, the neurotoxic effects induced by the MDMA metabolite N-Me-α-MeDA involved caspase 3 activation. In conclusion, this study evaluated the stability of MDMA metabolites in vitro, and demonstrated that the catechol MDMA metabolites and their GSH and NAC conjugates, rather than MDMA itself, exhibited neurotoxic actions in SH-SY5Y differentiated cells, which were differently affected by hyperthermia, thus highlighting a major role for reactive metabolites and hyperthermia in MDMA's neurotoxicity.

Amphetamine-related drugs neurotoxicity in humans and in experimental animals: Main mechanisms

“…Additionally, these MDMA metabolites promoted a significant mitochondrial dysfunction, as early as 24 hours after their application. Finally, a recent study, has confirmed that the toxicity induced by the catechol metabolites of MDMA is potentiated by hyperthermia, in line with earlier evidence (Barbosa et al, 2014). Taken together, these in vitro experiments have contributed to the elucidation of the mechanistic interactions of MDMA and its metabolites with cellular components.…”

Comparative study of the neurotoxicological effects of tramadol and tapentadol in SH-SY5Y cells

“…Caspase-3 activity was determined as described by Barbosa et al, 2014(Barbosa et al 2014. 50 l of each lysate was mixed with 200 L assay buffer (100 nM HEPES (pH 7.5), 20% (v/v) glycerol, 5 mM DTT, 0.5 mM EDTA) and 5 l of the caspase-3 peptide substrate Ac-DEVD-pNA (Sigma-Aldrich) (final concentration 80 M), in 96 well-plates, followed by incubation at 37°C for 24 hours.…”

Hyperthermia Increases Neurotoxicity Associated with Novel Methcathinones

“…Barbosa et al [17] have shown in a previous study that the toxicity of ecstasy and ecstasy metabolites on differentiated SH-SY5Y cells is increased at hyperthermic (40 • C) compared to normothermic (37 • C) conditions. Similarly, in the present study, we demonstrated that hyperthermic conditions increase the cytotoxicity of methcathinones by inducing apoptotic and necrotic cell death.…”

“…While the capacity of cathinones and many other recreational drugs to increase the body and brain temperature is well established, the effects of hyperthermia on neurotoxicity associated with these drugs is currently less well known [13]. Barbosa et al investigated the effect of ecstasy and ecstasy metabolites on SH-SY5Y cells under normothermic (37 • C) and hyperthermic (40 • C) conditions [17]. They found that the metabolites were more toxic than the parent compound and that the toxicity increased with higher temperature.…”