Freezing rates across (a) the three extinction sessions (Ext 1, 2, and 3) and the extinction retention test (ERT) and (b) social interaction (SI) time of rats treated with URB597 or vehicle (Veh) 1 h before the extinction sessions on day 7, 10, and 13. Freezing rates across (c) the three extinction sessions and the extinction retention test and (d) social interaction time of rats treated with JZL184 or vehicle 1 h before the extinction sessions on day 7, 10, and 13. Freezing rates across (e) the three extinction sessions and the extinction retention test and (f) social interaction time of rats treated with WIN55,212-2 or vehicle 1 h before the extinction sessions on day 7, 10, and 13. *P<0.05 URB597 0.1 mg/kg vs Veh. Data are expressed as mean±SEM (n=8–11 per group).