AM 251

Description

AM251 is a cannabinoid 1 (CB₁) receptor 1 antagonist. It binds to CB₁ receptors in rat forebrain membrane preparations (K_i = 7.5 nM) and is selective over CB₂ receptors in mouse spleen preparations (K_i = 2,290 nM) in radioligand binding assays. AM251 inhibits GTPγS binding induced by the CB receptor agonist CP 55,940 in HEK293 cells expressing human CB₁ receptors (EC₅₀ = 8 nM). AM251 (10 mg/kg) decreases immobility time in the forced swim test in wild-type but not CB₁ receptor-deficient mice. It reduces fasting-induced food intake and body weight gain in mice when administered at a dose of 30 mg/kg. AM251 also induces GTPγS binding in HEK293 cells expressing the orphan receptor GPR55 (EC₅₀ = 39 nM) and potentiates GABA-induced GABA_A receptor currents (EC₅₀ = 0.4 μM). It prevents TGF-β1-induced epithelial-to-mesenchymal transition (EMT), inhibits SMAD2/3 and p38 MAPK activation, and reduces the expression of EMT-related transcription factors in HK-2 renal tubule epithelial cells. AM251 induces cell cycle arrest at the G₂/M phase and apoptosis in A375 human melanoma cells.

Chemical Properties

White to Off-White Solid

Uses

Inhibitor of CB1 receptors. AM 251is a biarylpyrazole compound which has been considered for many years as the prototypical cannabinoid (CB) receptor antagonist

Uses

AM251, a CB₁ cannabinoid receptor antagonist, has been used in a study to determine its interaction with hippocampal neurons to enhance spatial memory in mice.

Definition

ChEBI: AM-251 is a carbohydrazide obtained by formal condensation of the carboxy group of 1-(2,4-dichlorophenyl)-5-(4-iodophenyl)-4-methyl-1H-pyrazole-3-carboxylic acid with the amino group of 1-aminopiperidine. An antagonist at the CB1 cannabinoid receptor. It has a role as a CB1 receptor antagonist, an apoptosis inducer, an antidepressant and an antineoplastic agent. It is a member of pyrazoles, a dichlorobenzene, an organoiodine compound, an amidopiperidine and a carbohydrazide.

Biological Activity

Potent CB 1 receptor antagonist (IC 50 = 8 nM, K i = 7.49 nM) that displays 306-fold selectivity over CB 2 receptors. Also potent GPR55 agonist (EC 50 = 39 nM). Also available as part of the Cannabinoid CB 1 Receptor Tocriset™ .

Biochem/physiol Actions

AM251 is a CB1 cannabinoid receptor antagonist.

storage

Room temperature

References

1) Gatley et al. (1996), 123I-labeled AM251: a radioiodinated ligand which binds in vivo to mouse brain cannabinoid CB1 receptors; Eur. J. Pharmacol., 307 331 2) Gatley et al. (1997), Binding of the non-classical cannabinoid CP 55,940 and the diarylpyrazole AM251 to rodent brain cannabinoid receptors; Life Sci., 61 191 3) Pertwee et al. (2005), Inverse agonism and neutral antagonism at cannabinoid CB1 receptors; Life Sci., 76 1307 4) Shearman et al. (2003), Antidepressant-like and anorectic effects of the cannabinoid CB1 receptor inverse agonist AM251 in mice; behave. Pharmacol., 14 573 5) Ryberg et al. (2007), The orphan receptor GPR55 is a novel cannabinoid receptor; Br. J. Pharmacol., 152 1092