Cannabinoid control of fear responses

Abstract

In 2002, a landmark study showed that the endogenous activity of the cannabinoid type-1 (CB1) receptors is necessary for extinction of conditioned freezing in mice (Marsicano G, Wotjak CT, Azad SC, Bisogno T, Rammes G, Cascio MG, Hermann H, Tang J, Hofmann C, Zieglgänsberger W, Di Marzo V, Lutz B. The endogenous cannabinoid system controls extinction of aversive memories. Nature. 2002 Aug 1;418(6897):530-4.). Since extinction of conditioned freezing is an important indicator of fear adaptation in animals and because our ability to control emotional responses is important to ensure adapted behaviors, the potential function of the endocannabinoid system (ECS) in such processes has generated a large interest. In this chapter, we will provide pieces of information linking the activity of the ECS and fear modulation.