Aim: Cannabinoid receptor type 1 (CB1R) and central nucleus of the amygdala (CeA) are both known to play crucial roles in processing fear responses. Despite extensive research on the role of endocannabinoids in fear, no evidence of a functional expression of CB1 in the CeA was reported so far. Here we investigated (i) the expression of CB1R in CeA in situ, (ii) the functionality of CB1R in the CeA by the application of a depolarization-induced suppression of excitation (DSE) protocol in vitro, and (iii) its possible role in fear expression and extinction in vivo. Methods: 1) Whole cell recordings in CeA neurons from adult wild type and CB1 knockout (-/-) mice were carried out. Glutamatergic EPSCs were evoked by electrical stimulation of the basolateral amygdala (BLA). DSE tests consisted of depolarization steps from -60 to 0 mV for 10 s and 5 s were applied. 2) In a classical fear conditioning paradigm, local pharmacology targeting the CeA or BLA was performed in behaving mice. Results: DSE (10s) reduced EPSCs amplitude in all cells (mean suppression (Y) to 61%±3%; n=10, while DSE (5s) reduced EPSCs in the 66% of cells (Y=to 83%±8%). Interestingly, DSE was absent in CB1-/- (Y=to 97%±3%, n=10) and blocked by the CB1- antagonist AM251 (2mM; Y= to 98%±3%; n=10). AM251 application by itself increased EPSCs amplitude (76%±8%; n=4). Conversely, the application of the cholinergic agonist carbachol (CCh; 1uM) reduced EPSCs amplitude (44%±7%; n=7). CCh enhanced DSE only after 5s (Y=to 85%±6%) and not after 10s depolarization (Y=to 70%±6%). Mice receiving AM251 in the CeA showed acutely an increased fear response, whereas no effects were detected upon application in BLA. However, upon repeated drug-free trials on consecutive days mice treated previously with AM251 in the BLA, but not in the CeA, showed increased freezing behavior. Conclusion: These results demonstrate for the first time the functional expression of CB1 in mouse CeA that constricts expression of conditioned fear.