ADX47273 administered prior to or after multi-session extinction did not enhance fear extinction. (Ai,Aii) Effects of prior administration of ADX47273 on extinction. Freezing during contextual fear conditioning (three footshocks) on Day 1 (Ai) and contextual extinction training during seven consecutive days (Aii). ADX47273 or vehicle was administered 30 min prior to training. Drug group, n = 9; vehicle group, n = 8. (Bi–Biii) Effects of post-extinction administration of ADX47273. Contextual fear conditioning on Day 1 (Bi) and multi-session extinction training during seven subsequent consecutive days. ADX47273 or vehicle was administered immediately after training (Bii). (Biii) LTM test performed 1 mo after extinction. Drug group, n = 12; vehicle group, n = 11.
