Our results are consistent with prior data showing that extinction training selectively increases anandamide levels in mouse BLA3 (but see Lin et al.53) and, furthermore, demonstrate that this increase in endogenous anandamide is augmented by AM3506 treatment. Examination of ex vivo 2-arachidonoylglycerol levels revealed only modest, statistically nonsignificant, increases in the BLA in CS–US, compared with CS-alone, trained mice. Moreover, AM3506 treatment had no effect on 2-arachidonoyl-glycerol levels either in the BLA or in the ventromedial prefrontal cortex or in the dorsal striatum (Supplementary Figure S4). These neurochemical data show that, by inhibiting FAAH, AM3506 boosts endogenous anandamide signaling in the BLA.
