Figure 5.
Interrupting brain-derived neurotrophic factor (BDNF) signaling in the basolateral complex of the amygdala (BLA) blocks 3,4-methylenedioxymethamphetamine's (MDMA's) extinction-enhancing effect. MDMA (7.8 mg kg−1) was administered systemically 30 min before extinction training. Anti-BDNF (0.2 μg) was infused bilaterally into the BLA 10 min before extinction training. (a) Anti-BDNF did not alter MDMA's effect on conditioned freezing during extinction training (F(1,20)=27.40, P<0.001 for the main effect of systemic treatment; (F(1,20)=0.458, P=0.506 for effect of infusion treatment; n=6 per group). (b) Anti-BDNF treatment before extinction training blocked MDMA-induced reductions in conditioned freezing during testing the following day (F(1,20)=4.62, P =0.044 for main effect of injection treatment; F(1,20)=9.58, P=0.006 for main effect of infusion; F(1,20)=7.38, P=0.013 for interaction of injection and infusion treatment; n=6 per group). (c) Anti-BDNF did not block MDMA's effect when it was given 10 h after extinction training (F(2,15)=11.86, P=0.01 for effect of treatment; n=6 per group). Bars represent mean±s.e. values of %freezing. *P<0.05, ^P<0.01, #P<0.001.