Setup of a Serotonin 2A Receptor (5-HT2AR) Bioassay: Demonstration of Its Applicability To Functionally Characterize Hallucinogenic New Psychoactive Substances and an Explanation Why 5-HT2AR Bioassays Are Not Suited for Universal Activity-Based Screening of Biofluids for New Psychoactive Substances
Analytical Chemistry November 14, 2019 Eline Pottie, Annelies Cannaert, Katleen van Uytfanghe et al. 29 citations
Classic hallucinogens, which activate the serotonin 2A receptor (5-HT2AR), represent the third largest category of new psychoactive substances. A new bioassay was developed that measures receptor activation by monitoring β-arrestin2 recruitment using a split-luciferase system. The assay determined potency and efficacy for various hallucinogens, including LSD, 5-MeO-DALT, mescaline, and several 2C compounds and their NBOMe derivatives, with EC50 values ranging from subnanomolar (NBOMes) to micromolar (mescaline) levels. When applied to plasma screening, blank samples showed pronounced receptor activation due to endogenous serotonin, confirmed by its elimination with a 5-HT2AR antagonist or MAO-A treatment, and by LC-HRMS analysis. The bioassay's main application is characterizing poorly understood serotonergic hallucinogens, as MAO-A metabolism of some compounds could bias detection in biofluids.