Figure 4. Exogenous GRP or GRPR antagonist did not affect expression of conditioned fear.

A) 600 ng GRP or 3000 ng GRPR antagonist (D-Phe⁶,Leu-NHEt¹³,des-Met¹⁴)-Bombesin(6–14) was infused into the amygdala of C57BL/6 mice, that were conditioned with 6 CS-US pairings as in Fig. 2C, 10 min prior to testing freezing in the conditioning context 24 h later. B) Effect of intra-amygdala infusion of 600 ng GRP 10 min prior to testing freezing in response to the CS. C) Location of the bilateral injection sites determined from post-hoc histological analysis.