In vitro characterization of new psychoactive substances at the μ-opioid, CB1, 5HT1A, and 5-HT2A receptors—On-target receptor potency and efficacy, and off-target effects
Anna Åstrand, Davide Guerrieri, Svante Vikingsson, Robert Kronstrand, Henrik Gréen
Forensic Science International October 23, 2020 DOI: 10.1016/j.forsciint.2020.110553 (opens in new tab)
Study at a glance
AI-extracted from the abstract| Characteristics | In vitro screening and dose-response characterization Peer reviewed |
|---|---|
| Topics | Serotonin |
| Keywords | Pharmacology Cannabinoid receptor agonists Hallucinogen Partial agonist Potency Opioid 5-HT Receptor Designer drug |
| Citations | 21 |
| Key points | Most NPS activated their intended receptor, with wide potency ranges and notable off-target effects, including μ-opioid activation by piperazines and phenethylamines, and 5-HT2A activation by a synthetic cannabinoid metabolite. |
Abstract
New psychoactive substances (NPS) appear on the recreational market on a monthly basis, with unclear toxicology, resulting in an increasing number of fatalities. Identification of drug targets and potencies is crucial for understanding and treating intoxications and for scheduling processes. In this study 60 NPS and metabolites belonging to opioids, cannabinoids and serotonergic hallucinogens classes were screened for in vitro activation of the μ-opioid, CB1, 5-HT1A and 5-HT2A receptors using the AequoZen cell system. Fentanyl and NBOMe analogues were chosen for full dose-response characterization of the μ-opioid and 5-HT2A receptors, respectively. Most substances activated their corresponding target receptor. The most potent μ-opioid receptor agonists were 2-fluorofentanyl (EC50 = 1.0 nM), carfentanil (EC50 = 2.7 nM) and acrylfentanyl (EC50 = 2.8 nM) and in total a >1500-fold difference was seen among the tested compounds. Moreover, furanylfentanyl, 4-methoxybutyrylfentanyl and valerylfentanyl acted as partial agonists of the μ-receptor. On the 5-HT2A receptor, bromo-dragonfly showed the highest potency (EC50 = 0.05 nM, 400 times more potent than LSD), followed by most NBOMe compounds with EC50 values ranging from 0.11 nM (for 25N-NBOMe) to 1.3 nM (for 25T4-NBOMe)). Off-target activation of the μ-opioid receptor was identified for piperazines, phenethylamines (in particular NBOMe and 2C compounds) and tryptamines. Moreover, the synthetic cannabinoid metabolite 3-carboxy indole PB-22 activated the 5-HT2A receptor. Bromo-dragonfly was the only compound that activated all four receptors. These results highlight the possible interplay of known and unknown NPS targets and unveil its complexity. Moreover, the detailed, quantitative information presented facilitates our further understanding of NPS toxicology.
Comparable studies
Other preclinical and animal studies on serotonin, most cited first.
| Study | Year | Design | Participants |
|---|---|---|---|
| Psilocybin induces rapid and persistent growth of dendritic spines in frontal cortex in vivo Mice | 2021 | Observational cohort | |
| Neurotoxicity of the psychedelic amphetamine, methylenedioxymethamphetamine. Rats (implied by typical neurochemical study context) | 1987 | Experimental study | |
| Psychedelics promote neuroplasticity through the activation of intracellular 5-HT2A receptors In vitro and in vivo (rodent) models | 2023 | Experimental study | |
| 3,4-Methylenedioxymethamphetamine and 3,4-methylenedioxyamphetamine destroy serotonin terminals in rat brain: quantification of neurodegeneration by measurement of [3H]paroxetine-labeled serotonin uptake sites. Rat brain | 1987 | Animal experiment | |
| Comparison of the monoamine transporters from human and mouse in their sensitivities to psychostimulant drugs Human and mouse dopamine, norepinephrine, and serotonin transporters expressed in cells | 2006 | In vitro laboratory study |
Citations in the library
Cited by 9
- Molecular and clinical aspects of potential neurotoxicity induced by new psychoactive stimulants and psychedelics Experimental Neurology June 4, 2021
- 25X-NBOMe compounds - chemistry, pharmacology and toxicology. A comprehensive review. Critical Reviews in Toxicology 2023
- Off-target activity of NBOMes and NBOMe analogs at the µ opioid receptor. Archives of Toxicology May 1, 2023
- Acute Effects of the Psychedelic Phenethylamine 25I-NBOMe in C57BL/6J Male Mice. International Journal of Molecular Sciences March 20, 2025
- 5-Methoxy-N,N-di-n-propyltryptamine (5-MeO-DPT): freebase and fumarate Acta Crystallographica. Section E, Crystallographic Communications April 13, 2021
and 4 more in the library
Cites 12
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- Receptor interaction profiles of novel N-2-methoxybenzyl (NBOMe) derivatives of 2,5-dimethoxy-substituted phenethylamines (2C drugs). Neuropharmacology December 1, 2015
- Neuropharmacology of New Psychoactive Substances (NPS): Focus on the Rewarding and Reinforcing Properties of Cannabimimetics and Amphetamine-Like Stimulants Frontiers in Neuroscience April 19, 2016
- Ligand-Dependent Conformations and Dynamics of the Serotonin 5-HT2A Receptor Determine Its Activation and Membrane-Driven Oligomerization Properties PLoS Computational Biology April 19, 2012
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and 7 more in the library