Systematic evaluation of a panel of 30 synthetic cannabinoid receptor agonists structurally related to MMB‐4en‐PICA, MDMB‐4en‐PINACA, ADB‐4en‐PINACA, and MMB‐4CN‐BUTINACA using a combination of binding and different CB1 receptor activation assays. Part III: The G protein pathway and critical comparison of different assays

Abstract

The present work is the last of a three-part study investigating a panel of 30 systematically designed synthetic cannabinoid receptor agonists (SCRAs) including features such as the 4-pentenyl tail and varying head groups including amides and esters of L-valine (MMB, AB), L-tert-leucine (ADB), and L-phenylalanine (APP), as well as adamantyl (A) and cumyl moieties (CUMYL). Here, we evaluated these SCRAs for their capacity to activate the human cannabinoid receptor 1 (CB 1 ) via indirect measurement of G protein recruitment. Furthermore, we comparatively evaluated the results obtained from three in vitro assays, based on the recruitment of β-arrestin 2 (βarr2 assay) or Gα i protein (mini-Gα i assay), or binding of [ 35 S]-GTPγS. The observed efficacies (E max ) varied depending on the conducted assay. Statistical analysis suggests that the population means of the relative intrinsic activity (RA i ) significantly differ for the [ 35 S]-GTPγS assay and the other two assays, but the population means of the βarr2 and mini-Gα i assays were not statistically different. Our data suggest that differences observed between the βarr2 and mini-Gα i assays are the best The contribution to this article by Patrick Juchli is independent from and unrelated to his function at PwC Switzerland.

The metabolism of the synthetic cannabinoids ADB‐BUTINACA and ADB‐4en‐PINACA and their detection in forensic toxicology casework and infused papers seized in prisons

“…MDMB‐4en‐PINACA, ADB‐4en‐PINACA, and ADB‐BUTINACA were all shown to have similar high potency in agreement with previously published data 19,20,30,31 . Variability in the user experience and the harms related to the use of SCRAs may not be affected by the different substances present but is more likely to be due to the unpredictable dose consumed, the mode of use, the impact of polydrug use, and personal factors related to the health of the person using the SCRA(s).…”

“…MDMB-4en-PINACA, ADB-4en-PINACA, and ADB-BUTINACA were all shown to have similar high potency in agreement with previously published data. 19,20,30,31 Variability in the user experience and the harms related to the use of SCRAs may not be affected by the different substances present but is more likely to be due to the unpredictable dose consumed, the mode of use, the impact of polydrug use, and personal factors related to the health of the person using the SCRA(s). As demonstrated by this and many other studies, tert-leucinamide (ADB-type) indazole-3-carboxamide SCRAs are often have similar potency to their tert-leucine methyl ester (MDMB-type) analogs, 19,20,30,31 and so their appearance on the SCRA market is not unexpected.…”

“…Metabolites marked with a yellow circle and a red square were detected in urine and blood, respectively, from authentic forensic toxicology cases [Colour figure can be viewed at wileyonlinelibrary.com] different jurisdictions. We provide an assessment of the potency of these two SCRAs using an alternative in vitro bioassay to those already reported 20,30,31 and compare their potency directly with that of MDMB-4en-PINACA, in order to discuss their relative potential for harm. Sample information and results for samples seized up to September 2020 have been reported previously.…”

“…Some prison authorities, including in Sweden, now regularly photocopy mail, providing prisoners with the copy and retaining/destroying the original; however, this approach varies due to specific legal issues around opening and retaining prisoner mail in different jurisdictions. We provide an assessment of the potency of these two SCRAs using an alternative in vitro bioassay to those already reported 20,30,31 and compare their potency directly with that of MDMB‐4en‐PINACA, in order to discuss their relative potential for harm.…”

Quantifying the Kinetics of Signaling and Arrestin Recruitment by Nervous System G-Protein Coupled Receptors

“…Unlike THC, some of these compounds have been associated with severe toxicological events, including seizures, cardiotoxicity, psychosis, hypothermia, and kidney injury, resulting in hundreds of hospitalizations and dozens of fatalities (Trecki et al, 2015 ; Adams et al, 2017 ). This increased morbidity and mortality of some of the SCRAs is correlated with a stronger efficacy for activation of the CB 1 receptor (Wiley et al, 2015 ; Banister et al, 2016 ; Cannaert et al, 2016 ; Hess et al, 2016 ; Costain et al, 2018 ; Gamage et al, 2018 ; Grafinger et al, 2021a , b ). For example, the SCRA 5F-MDMB-PICA was recently shown to activate the CB 1 receptor with an efficacy 260-fold higher than that of THC, demonstrated using the operational model of agonism and varying levels of receptor expression (Sachdev et al, 2019 ).…”