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Technical documents: SDS CoA Datasheet

Product overview

Name AM251
Purity >98%
Customer comments

It (AM251) works - bang for your buck! Works as described! Great technical support. Verified customer, UC Denver

Another quality product from Hello Bio - AM251 works as expected in our experiments and at a good price as well. We always order with confidence from Hello Bio, and are often surprised at how quickly we receive our products. Verified customer, University of South Carolina

Description Potent, selective CB1 receptor antagonist / inverse agonist
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AM251 product vial image | Hello Bio

Biological Data

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).

Solubility & Handling

Storage instructions Room temperature
Solubility overview Soluble in DMSO (100 mM) and in ethanol (25 mM)

This compound is light sensitive; we therefore recommend protecting the solid material and solutions from exposure to light.

Ongoing solubility of AM251 in aqueous solutions can be unpredictable and the compound can precipitate out of solution.

We therefore recommend:

  1. If possible, make up solutions and use immediately. Do not store solutions.
  2. When creating your stock solutions, ensure the compound is fully dissolved in DMSO (use heat to achieve this if necessary).
  3. Heat DMSO stock solution prior to addition to ACSF
  4. Heat your ACSF solution to ~42°C before addition of AM251.
  5. Mix the compound with ACSF immediately before use
Important This product is for RESEARCH USE ONLY and is not intended for therapeutic or diagnostic use. Not for human or veterinary use.



More Info


More Info

Chemical Data

Purity >98%
Chemical name N-(Piperidin-1-yl)-5-(4-iodophenyl) -1-(2,4-dichlorophenyl)-4-methyl-1H-pyrazole-3-car boxamide
Molecular Weight 555.24
Chemical structure AM 251 [183232-66-8] Chemical Structure
Molecular Formula C22H21Cl2IN4O
CAS Number 183232-66-8
PubChem identifier 2125
Source Synthetic
InChi InChI=1S/C22H21Cl2IN4O/c1-14-20(22(30)27-28-11-3-2-4-12-28)26-29(19-10-7-16(23)13-18(19)24)21(14)15-5-8-17(25)9-6-15/h5-10,13H,2-4,11-12H2,1H3,(H,27,30)
MDL number MFCD01861181
Appearance White solid

References for AM251

References are publications that support the biological activity of the product
  • 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
  • The cannabinoid CB1 receptor antagonists SR141716 and AM251 directly potentiate GABA(A) receptors.

    Baur et al (2012) Br J Pharmacol 165(8) : 2479-84
  • 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
  • The orphan receptor GPR55 is a novel cannabinoid receptor.

    Ryberg et al (2007) Br J Pharmacol 152(7) : 1092-101.
  • Structure-activity relationships of pyrazole derivatives as cannabinoid receptor antagonists.

    Lan et al (1999) J Med Chem 42(4) : 769-76

5 Item(s)

These publications cite the use of AM251 purchased from Hello Bio:
  • Activity-Dependent Modulation of Tonic GABA Currents by Endocannabinoids in Hirudo verbana

    Paulsen RT et al (2022) Front Synaptic Neurosci 14 : 760330
    PubMedID: 35368247
  • Differential regulation of prelimbic and thalamic transmission to the basolateral amygdala by acetylcholine receptors

    Mott et al (2021) bioRxiv https://doi.org/10.1101/2021.12.28.474396 : doi
  • Differential regulation of prelimbic and thalamic transmission to the basolateral amygdala by acetylcholine receptors

    Tryon et al (2019) University of Columbia : Thesis

3 Item(s)