NPY is an anxiolytic compound when admistered into the central nervous system. Furthermore, NPYs expression levels are affected by external stressors. When we examined the effect of a stressor on NPY expression within the amygdala we were able to show different effects following acute and repeated stress-exposure and to correlate this with anxiety-related behavior on the elevated plus-maze, leading to the conclusion that NPY-expression partakes in behavioral adaptation to stressors (Thorsell et al., 1998Thorsell et al., 1999). Furthermore, rats over-expressing NPY in the hippocampus lacked fear-linked suppression of behavior and demonstrated behavioral insensitivity to restraint stress measured on the elevated plus-maze (Thorsell et al., 2000).
