To date, depression is one of the most common psychiatric illnesses with serious health, social and even economic impact. One third of patients do not respond to the currently available pharmacotherapy or develop severe side effects. The neurobiological background of the complex pathomechanisms is not fully understood. We aim to explore the unknown underlying factors in mouse models of mood disorders in a complex behavioral, neuroendocrine, functional-neuromorphological approach supplemented with molecular biological methods. We focus on serotonin and corticotropin-releasing hormone-containing brainstem centers which play crucial role in stress adaptation response.