FAAH is a serine hydrolase that catalyzes the degradation of AEA into arachidonic acid and ethanolamine (Ahn et al., 2008). Initial ISH studies by Cravatt and co-workers revealed an intense ISH signal within the amygdala, and specifically within the BLA (Thomas et al., 1997). These studies were closely followed by immunohistochemical localization of FAAH within the central nervous system using a C-terminal antibody (Tsou et al., 1998b). This study found intracellular punctate staining preferentially localized to large principal neurons of the rat brain, a pattern consistent with intracellular membrane localization of the protein. Within the BLA, FAAH immunoreactivity was described as moderate to strong. However, within the CeA, smaller round neurons also expressed cytoplasmic FAAH immunoreactivity, although to a lesser degree than that of the BLA.
