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Product overview

  • Name
  • Short description
    Potent, selective CB1 receptor antagonist / inverse agonist
  • Biological description

    AM251 is a potent and selective prototypic cannabinoid 1 receptor (CB1) antagonist / inverse agonist (IC50 = 8 nM and Ki = 7.49 nM).

    AM251 shows ~306-fold selectivity over CB2 receptors. Structural analog of SR141716A.

    Also acts as a potent GPR55 orphan receptor agonist (EC50 = 39 nM) and shows activity at the µ-opioid receptor (MOR) (Ki = 251 nM). Additionally, directly potentiates GABAreceptors.

    AM251 attenuates responses to established cannabinoid receptor agonists in vitro or in vivo.

    Blocks heterosynaptic long term depression (LTD).

  • Biological action
  • Purity
  • Special requirements

    It (AM 251) works - bang for your buck! Works as described! Great technical support. Verified customer, UC Denver

  • Citations



  • Chemical name
    N-(Piperidin-1-yl)-5-(4-iodophenyl) -1-(2,4-dichlorophenyl)-4-methyl-1H-pyrazole-3-car boxamide
  • Molecular Weight
  • Chemical structure
    AM 251 [183232-66-8]
  • Molecular Formula
  • CAS Number
  • PubChem identifier
  • Source
  • InChi
  • InChiKey
  • MDL number
  • Appearance
    White solid

Storing and Using Your Product

  • Storage instructions
    Room temperature
  • Solubility overview
    Soluble in DMSO (100 mM) and in ethanol (25 mM)
  • Important
    This product is for RESEARCH USE ONLY and is not intended for therapeutic or diagnostic use. Not for human or veterinary use.

References for AM251

  • AM-251 and SR141716 act as direct antagonists at mu-opioid receptors: implications for opioid/cannabinoid interaction studies.

    Seely et al (2012) Neuropharmacology 63(5) : 905-15
    PubMedID: 22771770
  • Cannabinoid CB1 receptor antagonists attenuate cocaine's rewarding effects: experiments with self-administration and brain-stimulation reward in rats.

    Xi et al (2008) Neuropsychopharmacology 33(7) : 1735-45
    PubMedID: 17728698
  • Structure-activity relationships of pyrazole derivatives as cannabinoid receptor antagonists.

    Lan et al (1999) J Med Chem 42(4) : 769-76
    PubMedID: 10052983
  • The orphan receptor GPR55 is a novel cannabinoid receptor.

    Ryberg et al (2007) Br J Pharmacol 152(7) : 1092-101.
    PubMedID: 17876302
  • The cannabinoid CB1 receptor antagonists SR141716 and AM251 directly potentiate GABA(A) receptors.

    Baur et al (2012) Br J Pharmacol 165(8) : 2479-84
    PubMedID: 21470203
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Reviews & Product Guides


  • Verified customer, UC Denver

    It (AM 251) works - bang for your buck! Works as described! Great technical support.