Org 27569

Org 27569 is a drug which acts as a potent and selective positive allosteric modulator of the cannabinoid CB₁ receptor. Studies in vitro suggest that it binds to a regulatory site on the CB₁ receptor target, causing a conformational change that increases the binding affinity of CB₁ agonists such as CP 55,940, while decreasing the binding affinity of CB₁ antagonists or inverse agonists such as rimonabant. However while Org 27569 increases the ability of CB₁ agonists to bind to the receptor, it decreases their efficacy at stimulating second messenger signalling once bound, and so in practice behaves as an insurmountable antagonist of CB₁ receptor function.