A) The Tac2 product, Neurokinin B (NkB) is detected by immunocytochemistry in mouse amygdala cell culture. NkB is highly expressed in the soma and in the dendrites. Red is NkB signal. Blue is neuronal nucleus, NeuN. Scale bar = 25 μm. B) Immunohistochemistry studies show high expression of NkB in the central amygdala (CeA). Scale bar = 125 μm. C) NkB is up-regulated at 2 hrs in the amygdala after fear conditioning. **P ≤0.01 vs Home Cage, N=6-8 per group. D) Amygdala cell culture with osanetant, a potent and specific neurokinin 3 (Nk3R) antagonist. Incubation with 20 μg and 40 μg of osanetant enhances Nk3R mRNA levels. This suggests that osanetant activates Nk3R and its downstream signaling in the amygdala. *P ≤0.05 vs Veh, **P ≤0.01 vs Veh, N=2 per group. Mean + SEM is shown.