Effects of chronic stress on dendritic arborization in the central and extended amygdala.

A differential role has been suggested for two important areas in the neural circuitry of stress, central nucleus of the amygdala (CeA) and bed nucleus of stria terminalis (BNST) in the extended amygdala, in regulating fear versus anxiety. Since chronic stress enhances anxiety and consolidation of aversive memories, we examined the effects of chronic immobilization stress (CIS) on neuronal morphology in the CeA and BNST of rats. In contrast to previous reports of stress-induced atrophy in the hippocampus, CIS does not cause dendritic atrophy in CeA and BNST neurons. While dendritic arborization in CeA neurons remains unaffected, it increases in BNST neurons after CIS. These results suggest a role for dendritic remodeling of BNST neurons in stress-induced facilitation of anxiety.