Potent CB1 receptor allosteric modulator (pEC50 = 8.24). Significantly increases binding of the CB1 agonist [3H]CP 55.940 (pKb = 5.67) and decreases binding of the CB1 inverse agonist [3H]SR 141716A (pKb = 5.95). Inhibits CB1 receptor antagonist efficacy in vitro (pKb = 7.57).