Background
Fear and anxiety are integrated in the amygdaloid nuclei and involve the interplay of the amygdala with various other brain areas. Neuropeptides play a critical role in regulating these processes. Neuropeptide Y (NPY) is highly expressed in limbic brain areas, including the amygdala. Depending on the receptor subtypes involved (Y1, Y2 or Y4), NPY has different, in part opposing effects on anxiety, fear and depression-related behaviors.