|Systematic (IUPAC) name|
|CAS Registry Number|
|Molecular mass||555.238 g/mol|
AM-251 is an inverse agonist at the CB1 cannabinoid receptor. AM-251 is structurally very close to SR141716A (rimonabant); both are biarylpyrazole cannabinoid receptor antagonists. In AM-251 the p-chloro group attached to the phenyl substituent at C-5 of the pyrazole ring is replaced with a p-iodo group. The resulting compound exhibits slightly better binding affinity for the CB1 receptor (with a Ki value of 7.5nM) than SR141716A, which has a Ki value of 11.5nM, AM-251 is, however, about two-fold more selective for the CB1 receptor when compared to SR141716A. Like SR141716A, it is additionally a μ-opioid receptor antagonist.
- Lan, R., Liu, Q., Fan, P., et al. Structure-activity relationships of pyrazole derivatives as cannabinoid receptor antagonists. J Med Chem 42 769-776 (1999). PubMed 10052983
- AM-251 and rimonabant act as direct antagonists at mu-opioid receptors: implications for opioid/cannabinoid interaction studies. Neuropharmacology. 2012 Oct;63(5):905-15. doi: 10.1016/j.neuropharm.2012.06.046. Epub 2012 Jul 4. PMID 22771770 PMCID: PMC3408547