Figure 7. Deoxygedunin enhances acquisition of conditioned fear, a BDNF-dependent learning process.

(A) Outline of Deoxygedunin (DG) fear conditioning experiment. Mice were handled and habituated to testing context on the first two days, followed by systemic DG (5 mg/kg, i.p.) 1 hr prior to fear conditioning (5, 0.5mA shock-tone pairings), followed by testing in the absence of drug on days 4–5. (B) Shock reactivity during fear conditioning, demonstrating that the acute effects of the drug did not affect pain or fear responsiveness. (C) Total freezing to the conditioned cue was significantly greater on both the first and second testing day in the mice that received DG with fear conditioning. (D & E), Freezing activity during the habituation period and first 4 CS presentations on test day 1 (D) or 2 (E). There was no difference in animal activity in the test chamber prior to the onset of the conditioned cue, or between cue presentations. However there was significantly increased fear, as measured with conditioned freezing, during conditioned stimuli (CS). Dark bars represent tone conditioned stimulus presentations; **, p<0.01, *, p<0.05 between DG and vehicle groups.