Corticotropin-releasing hormone (CRH) plays a pivotal role in the response of an organism to various stressors. Furthermore, chronic elevated levels of CRH are implicated in human stress-related and affective disorders, including major depression. To gain more insight into the relationship between hyperactivity of the CRH system and associated neuroendocrine, autonomic, physiological and behavioral changes, we have developed a transgenic mouse model of lifelong CRH overproduction (CRH-OE).
In this study, we explored the behavioural consequences of chronic CRH overproduction in mice of two established transgenic lines (CRH-OE2122 and CRH-OE2123) in behavioural paradigms reflecting different aspects of stress, anxiety and depression. These paradigms include the open field test, which is based on free exploration of an unfamiliar environment, the elevated plus maze, which is associated with anxiety-like responses, and the forced swim test, which can detect (anti-)depressant-like behaviors.
The Observer and EthoVision proved to be very useful tools in this study, in that they allowed easy recording and analysis of specific behaviours, resulting in an extensive description of the behavioural profile of the mutant mice overexpressing CRH.