AM251 is a cannabinoid receptor type 1 (CB1) antagonist with an IC50 of 8nM and a G protein-coupled receptor 55 (GPR55) agonist with an EC50 of 39nM[1] [2]. AM251 plays an important role in physiological processes such as cognition and immune function, and may be potentially valuable in the prevention and mitigation of fibrosis.
AM251 (10μM, 24hours) suppressed epithelial-mesenchymal transition of renal tubular epithelial cells without cytotoxicity[3]. AM251 (10μM, 48hours) had an inhibitory effect on fibroblasts differentiation into myofibroblasts and collagen production induced by TGF-β in primary human fibroblasts cultures, with a pIC50 of 5.5[4]. AM251 (IC50: 5μmol/L) induced apoptosis and G2/M cell cycle arrest in A375 human melanoma cells[5].
AM251 (3mg/kg, i.p) treatment led to an increase in pro-inflammatory cytokines in rats, while decreasing fat pad mass and altering plasma hormone levels, inducing weight loss and adiposity reduction[6]. AM251 (1mg/kg, i.p.) improved recognition memory in rats without alteration of their psychomotor activity and anxiety[7]. AM251 (1mg/kg, i.p.) attenuated ataxia-related deficits in a cerebellar ataxia model, improved motor activity and blocked Purkinje cells neuronal degeneration in ataxic animals[8].
References:
[1] Bruno A, Lembo F, Novellino E, Stornaiuolo M, Marinelli L. Beyond radio-displacement techniques for identification of CB1 ligands: the first application of a fluorescence-quenching assay. Sci Rep. 2014 Jan 20;4:3757. doi: 10.1038/srep03757. PMID: 24441508; PMCID: PMC3895875.
[2] Sharir H, Abood ME. Pharmacological characterization of GPR55, a putative cannabinoid receptor. Pharmacol Ther. 2010 Jun;126(3):301-13. doi: 10.1016/j.pharmthera.2010.02.004. Epub 2010 Mar 16. PMID: 20298715; PMCID: PMC2874616.
[3] Yoshinaga T, Uwabe K, Naito S, Higashino K, Nakano T, Numata Y, Kihara A. AM251 Suppresses Epithelial-Mesenchymal Transition of Renal Tubular Epithelial Cells. PLoS One. 2016 Dec 9;11(12):e0167848. doi: 10.1371/journal.pone.0167848. PMID: 27936102; PMCID: PMC5148003.
[4] Correia-Sá IB, Carvalho CM, Serrão PV, Machado VA, Carvalho SO, Marques M, Vieira-Coelho MA. AM251, a cannabinoid receptor 1 antagonist, prevents human fibroblasts differentiation and collagen deposition induced by TGF-β - An in vitro study. Eur J Pharmacol. 2021 Feb 5;892:173738. doi: 10.1016/j.ejphar.2020.173738. Epub 2020 Nov 19. PMID: 33220269.
[5] Carpi S, Fogli S, Romanini A, Pellegrino M, Adinolfi B, Podestà A, Costa B, Da Pozzo E, Martini C, Breschi MC, Nieri P. AM251 induces apoptosis and G2/M cell cycle arrest in A375 human melanoma cells. Anticancer Drugs. 2015 Aug;26(7):754-62. doi: 10.1097/CAD.0000000000000246. PMID: 25974027.
[6] O'Keefe L, Vu T, Simcocks AC, Jenkin KA, Mathai ML, Hryciw DH, Hutchinson DS, McAinch AJ. CB1 Ligand AM251 Induces Weight Loss and Fat Reduction in Addition to Increased Systemic Inflammation in Diet-Induced Obesity. Int J Mol Sci. 2022 Sep 28;23(19):11447. doi: 10.3390/ijms231911447. PMID: 36232744; PMCID: PMC9569643.
[7] Bialuk I, Winnicka MM. AM251, cannabinoids receptors ligand, improves recognition memory in rats. Pharmacol Rep. 2011;63(3):670-9. doi: 10.1016/s1734-1140(11)70578-3. PMID: 21857077.
[8] Ranjbar H, Soti M, Kohlmeier KA, Sheibani V, Ahmadi-Zeidabadi M, Rafiepour K, Shabani M. The cannabinoid antagonist, AM251 attenuates ataxia related deficiencies in a cerebellar ataxic model. Int J Neurosci. 2024 May;134(5):522-529. doi: 10.1080/00207454.2022.2126771. Epub 2022 Sep 30. PMID: 36120979.
AM251是一种 1 型大麻素受体 (CB1) 拮抗剂,IC50为8nM,同时也是G蛋白偶联受体55 (GPR55) 激动剂,其EC50为39nM[1] [2]。AM251在认知和免疫功能等生理过程中发挥重要作用,在预防和缓解纤维化方面可能具有潜在价值。
AM251 (10μM,24hours) 可抑制肾小管上皮细胞的上皮-间质转化,且无细胞毒性[3]。AM251 (10μM,48hours) 对原代人成纤维细胞培养物中由TGF-β诱导的成纤维细胞向肌成纤维细胞分化和胶原生成具有抑制作用,pIC50为5.5[4]。AM251 (IC50:5μmol/L) 可诱导A375人黑色素瘤细胞凋亡和G2/M细胞周期停滞[5]。
AM251 (3mg/kg, i.p) 可导致大鼠体内促炎细胞因子增加,同时减少脂肪垫质量并改变血浆激素水平,诱导体重下降和脂肪减少[6]。AM251 (1mg/kg, i.p.) 可改善大鼠的识别记忆,但不会改变其精神运动活动和焦虑[7]。AM251 (1mg/kg, i.p.) 可减轻小脑共济失调模型中与共济失调相关的缺陷,改善共济失调动物的运动活动并阻止Purkinje细胞神经元变性[8]。
















