Departments of Pharmacology and Toxicology, College of Medicine, University of Arkansas for Medical Sciences, Little Rock, AK 72205, USA.
Drug Metab Dispos. 2012 Nov;40(11):2174-84. doi: 10.1124/dmd.112.047530. Epub 2012 Aug 17.
Abuse of synthetic cannabinoids (SCs), such as [1-naphthalenyl-(1-pentyl-1H-indol-3-yl]-methanone (JWH-018) and [1-(5-fluoropentyl)-1H-indol-3-yl]-1-naphthalenyl-methanone (AM2201), is increasing at an alarming rate. Although very little is known about the metabolism and toxicology of these popular designer drugs, mass spectrometric analysis of human urine specimens after JWH-018 and AM2201 exposure identified monohydroxylated and carboxylated derivatives as major metabolites. The present study extends these initial findings by testing the hypothesis that JWH-018 and its fluorinated counterpart AM2201 are subject to cytochrome P450 (P450)-mediated oxidation, forming potent hydroxylated metabolites that retain significant affinity and activity at the cannabinoid 1 (CB(1)) receptor. Kinetic analysis using human liver microsomes and recombinant human protein identified CYP2C9 and CYP1A2 as major P450s involved in the oxidation of the JWH-018 and AM2201. In vitro metabolite formation mirrored human urinary metabolic profiles, and each of the primary enzymes exhibited high affinity (K(m) = 0.81-7.3 μM) and low to high reaction velocities (V(max) = 0.0053-2.7 nmol of product · min(-1) · nmol protein(-1)). The contribution of CYP2C19, 2D6, 2E1, and 3A4 in the hepatic metabolic clearance of these synthetic cannabinoids was minimal (f(m) = <0.2). In vitro studies demonstrated that the primary metabolites produced in humans display high affinity and intrinsic activity at the CB(1) receptor, which was attenuated by the CB(1) receptor antagonist (6aR,10aR)-3-(1-methanesulfonylamino-4-hexyn-6-yl)-6a,7,10,10a-tetrahydro-6,6,9-trimethyl-6H-dibenzo[b,d]pyran (O-2050). Results from the present study provide critical, missing data related to potential toxicological properties of "K2" parent compounds and their human metabolites, including mechanism(s) of action at cannabinoid receptors.
滥用合成大麻素（SCs），如[1-萘基-（1-戊基-1H-吲哚-3-基]甲酮（JWH-018）和[1-（5-氟戊基）-1H-吲哚-3-基]-1-萘基甲酮（AM2201），正在以惊人的速度增加。尽管人们对这些流行的设计药物的代谢和毒理学知之甚少，但对 JWH-018 和 AM2201 暴露后人体尿液标本的质谱分析鉴定出单羟基化和羧基化衍生物为主要代谢物。本研究通过测试以下假设来扩展这些初步发现：JWH-018 及其氟化对应物 AM2201 受到细胞色素 P450（P450）介导的氧化作用，形成具有显著亲和力和活性的有效羟基化代谢物，保留在大麻素 1（CB1）受体。使用人肝微粒体和重组人蛋白进行的动力学分析鉴定出 CYP2C9 和 CYP1A2 是参与 JWH-018 和 AM2201 氧化的主要 P450。体外代谢产物的形成与人体尿液代谢谱相吻合，每种主要酶均表现出高亲和力（K m=0.81-7.3 μM）和低至高反应速度（V max=0.0053-2.7 nmol 的产物·min -1·nmol 蛋白 -1）。CYP2C19、2D6、2E1 和 3A4 在这些合成大麻素肝代谢清除中的贡献最小（f m=<0.2）。体外研究表明，在人类中产生的主要代谢物在 CB1 受体上具有高亲和力和内在活性，该活性被 CB1 受体拮抗剂（6aR，10aR）-3-（1-甲磺酰氨基-4-己炔-6-基）-6a，7，10，10a-四氢-6，6，9-三甲基-6H-二苯并[b，d]吡喃（O-2050）减弱。本研究的结果提供了与“K2”母体化合物及其人体代谢物的潜在毒理学性质相关的关键缺失数据，包括在大麻素受体上的作用机制。
