Hunter D J Webb, David B Finlay, Shuli Chen, Andrea J Vernall, Eric Sparkes, Samuel D Banister, Rhonda J Rosengren, Michelle Glass
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引用次数: 1
Abstract
Purpose: AMB-FUBINACA is a synthetic cannabinoid receptor agonist (SCRA) which is primarily metabolised by hepatic enzymes producing AMB-FUBINACA carboxylic acid. The metabolising enzymes associated with this biotransformation remain unknown. This study aimed to determine if AMB-FUBINACA metabolism could be reduced in the presence of carboxylesterase (CES) inhibitors and recreational drugs commonly consumed with it. The affinity and activity of the AMB-FUBINACA acid metabolite at the cannabinoid type-1 receptor (CB1) was investigated to determine the activity of the metabolite.
Methods: The effect of CES1 and CES2 inhibitors, and delta-9-tetrahydrocannabinol (Δ9-THC) on AMB-FUBINACA metabolism were determined using both human liver microsomes (HLM) and recombinant carboxylesterases. Radioligand binding and cAMP assays comparing AMB-FUBINACA and AMB-FUBINACA acid were carried out in HEK293 cells expressing human CB1.
Results: AMB-FUBINACA was rapidly metabolised by HLM in the presence and absence of NADPH. Additionally, CES1 and CES2 inhibitors both significantly reduced AMB-FUBINACA metabolism. Furthermore, digitonin (100 µM) significantly inhibited CES1-mediated metabolism of AMB-FUBINACA by ~ 56%, while the effects elicited by Δ9-THC were not statistically significant. AMB-FUBINACA acid produced only 26% radioligand displacement consistent with low affinity binding. In cAMP assays, the potency of AMB-FUBINACA was ~ 3000-fold greater at CB1 as compared to the acid metabolite.
Conclusions: CES1A1 was identified as the main hepatic enzyme responsible for the metabolism of AMB-FUBINACA to its less potent carboxylic acid metabolite. This biotransformation was significantly inhibited by digitonin. Since other xenobiotics may also inhibit similar SCRA metabolic pathways, understanding these interactions may elucidate why some users experience high levels of harm following SCRA use.
期刊介绍：
The journal Forensic Toxicology provides an international forum for publication of studies on toxic substances, drugs of abuse, doping agents, chemical warfare agents, and their metabolisms and analyses, which are related to laws and ethics. It includes original articles, reviews, mini-reviews, short communications, and case reports. Although a major focus of the journal is on the development or improvement of analytical methods for the above-mentioned chemicals in human matrices, appropriate studies with animal experiments are also published.
Forensic Toxicology is the official publication of the Japanese Association of Forensic Toxicology (JAFT) and is the continuation of the Japanese Journal of Forensic Toxicology (ISSN 0915-9606).
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