OPEN Foundation

A. Sulima

Sensitization to the prosocial effects of 3,4-methylenedioxymethamphetamine (MDMA).

Abstract

The recreational drug 3,4-methylenedioxymethamphetamine (MDMA) has well documented prosocial effects and is currently under clinical investigation as a treatment for patients with PTSD, autism, and other conditions. Early clinical trials have found that MDMA-assisted therapy may have robust long-lasting therapeutic effects, yet the mechanism by which acute treatments produce these long-term effects is unclear. Sensitization to certain behavioral drug effects is a common rodent model used to assess long-lasting neurobiological adaptations induced by acute drug treatments. Nine independent experiments were undertaken to investigate if and how mice sensitize to the prosocial effects of MDMA. When treated with 7.8 mg/kg MDMA and paired every other day for a week, MDMA-induced social interaction increased precipitously across treatment sessions. This previously unreported phenomenon was investigated and found to be heavily influenced by a social context and 5-HT2AR activation. Social sensitization did not appear to develop if mice were administered MDMA in isolation, and pretreatment with MDL100907, a selective 5-HT2AR antagonist, inhibited the development of social sensitization. However, when MDL100907 was administered to mice that had already been sensitized, it did not attenuate social interaction, suggesting that 5-HT2AR activity may be necessary for the development of social sensitization but not the expression of MDMA-induced social behavior. Additional investigation is warranted to further explore the phenomenon of social sensitization and to determine the underlying neurobiological mechanisms.
Curry, D. W., Berro, L. F., Belkoff, A. R., Sulima, A., Rice, K. C., & Howell, L. L. (2019). Sensitization to the prosocial effects of 3, 4-methylenedioxymethamphetamine (MDMA). Neuropharmacology151, 13-20., https://doi.org/10.1016/j.neuropharm.2019.03.017
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Comparative neuropharmacology of N-(2-methoxybenzyl)-2,5-dimethoxyphenethylamine (NBOMe) hallucinogens and their 2C counterparts in male rats

Abstract

2,5-Dimethoxyphenethylamines (2C compounds) are 5-HT2A/2C receptor agonists that induce hallucinogenic effects. N-methoxybenzylation of 2C compounds markedly increases their affinity for 5-HT2A receptors, and two such analogs, 2-(4-chloro-2,5-dimethoxyphenyl)-N-[(2-methoxyphenyl)methyl]ethanamine (25C-NBOMe) and 2-(4-iodo-2,5-dimethoxyphenyl)-N-[(2-methoxyphenyl)methyl]ethanamine (25I-NBOMe), have emerged in recreational drug markets. Here, we investigated the neuropharmacology of 25C-NBOMe and 25I-NBOMe in rats, as compared to their 2C analogs and the prototypical 5-HT2A/2C agonist 1-(4-iodo-2,5-dimethoxyphenyl)propan-2-amine (DOI). Compounds were tested in vitro using 5-HT2A receptor binding and calcium mobilization assays. For in vivo experiments, 25C-NBOMe (0.01-0.3 mg/kg), 25I-NBOMe (0.01-0.3 mg/kg), 2-(4-chloro-2,5-dimethoxyphenyl)ethanamine (2C-C) (0.1-3.0 mg/kg), 2-(4-iodo-2,5-dimethoxyphenyl)ethanamine (2C-I) (0.1-3.0 mg/kg) and DOI (0.03-1.0 mg/kg) were administered subcutaneously (sc) to male rats, and 5-HT2A-mediated behaviors were assessed. NBOMes displayed higher affinity for 5-HT2A receptors than their 2C counterparts but were substantially weaker in functional assays. 25C-NBOMe and 25I-NBOMe were much more potent at inducing wet dog shakes (WDS) and back muscle contractions (BMC) when compared to 2C-C and 2C-I. Pretreatment with the selective 5-HT2A antagonist (R)-(2,3-dimethoxyphenyl){1-[2-(4-fluorophenyl)ethyl]-4-piperidinyl}methanol (M100907) reversed behaviors produced by all agonists. Interestingly, binding affinities at the 5-HT2A receptor were significantly correlated with potencies to induce BMC but not WDS. Our findings show that NBOMes are highly potent 5-HT2A agonists in rats, similar to effects in mice, and consistent with the reported hallucinogenic effects in human users.
Elmore, J. S., Decker, A. M., Sulima, A., Rice, K. C., Partilla, J. S., Blough, B. E., & Baumann, M. H. (2018). Comparative neuropharmacology of N-(2-methoxybenzyl)-2, 5-dimethoxyphenethylamine (NBOMe) hallucinogens and their 2C counterparts in male rats. Neuropharmacology. 10.1016/j.neuropharm.2018.02.033
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