CRF expression and activity following PC exposure has yet to be measured, but would be highly informative, since it: 1) can drive the observed ACTH changes; 2) can play a critical role in stress reactive behaviors (anxiety and depression); and 3) is active in brain regions where decreases in 5-HT1A receptors may play important roles [50,198,208]. Here, CRH is linked to major depressive disorder.