Fig. 6.

Propranolol mitigates the immediate extinction deficit. Propranolol administration immediately after fear conditioning (A) reduced both baseline (BL) and freezing during the immediate extinction session (B, 30 min after conditioning). Propranolol facilitated the recall of extinction during a retention test conducted 48 h after extinction (vehicle, n = 7; propranolol, n = 7) (C). This effect on freezing was not due to impaired consolidation of the fear conditioning memory. Rats that were administered propranolol immediately after conditioning (D), but not extinguished exhibited reductions in freezing early in the no-extinction session (E, context exposure only) and high levels of freezing during the retention test that did not differ from vehicle-treated controls (vehicle, n = 8; propranolol, n = 8) (F). Gray bars denote the 3-min baseline (BL) period before delivery of conditioning or extinction trials. *P < 0.05 vs. propranolol. All values are means ± SEM.