Corticosterone regulates fear memory via Rac1 activity in the hippocampus

•Stress generates fear-specific memories and G-protein Rac1 may play a role in this.•Stress and exogenous corticosterone downregulated activity Rac1.•RU38486, glucocorticoid receptor agonist, recovered activity Rac1 and decreased memory.•The glucocorticoid receptor inhibitor NSC23766 increased fear memory retrieval.•Rac1 may thus be therapeutic targets in stress and memory disorders.