The CeA is part of a conceptual macrostructure called the extended amygdala that is profoundly implicated in alcohol and drug reinforcement and dependence (Koob 2003, 2008). The dynorphin/KOR system plays a key role in stress and addiction processes (Bruchas et al., 2010; Wee and Koob, 2010), and antagonism of KOR selectively reduces alcohol self-administration in alcohol-dependent rats (Walker et al., 2012). We showed here that the dynorphin/KOR system tonically influences CeA activity. An active dynorphin/KOR tone has not been observed in other limbic structures such as the bed nucleus of the stria terminalis, basolateral amygdala or nucleus accumbens (Huge et al., 2009; Mu et al., 2011; Li et al., 2012). It remains to be seen whether chronic alcohol produces neuroadaptations in this KOR tone in CeA during the transition to dependence.
