Measuring Behavior 2005: Chourbaij et al.

The significance of multiple stressors in prehistory for the specificity in the learned helplessness model of depression in mice

S. Chourbaji, C. Dormann, C. Zacher and P. Gass

Central Institute of Mental Health (CIMH), Mannheim, Germany

Animal models currently represent the only possibility to gain further insights into the mechanisms involved in the pathogenesis of particular diseases. Depression, in this respect, constitutes a major challenge since the characterization of disease-specific traits is complicated due to the multifactorial derivation. The understanding of associations of diverse factors, which have to be considered to affect the course of the disease, therefore represents a major target of behavioral animal models of depression. Working on a model, like the learned helplessness, consequently requires exact consideration of modulating aspects to ensure representative results. This study aims to elucidate potential distorting factors such as housing conditions of the experimental animals, which are controversially debated to affect the animals’ emotionality. To guarantee a specific readout which permits concrete statements regarding the quality of our model, we compared the effects of different social as well as environmental factors with regard to general and helplessness-specific effects on behavior. Furthermore we confirmed the model by a pharmacological validation, simultaneously monitoring effects of the obligatory handling procedure. Particularly in studies of depression and emotionality it is important to establish standardized protocols, involving the animal’s environment, to be able to precisely assess potential sources of stress and exclude artifacts. The design and modification of animal models such as learned helplessness subsequently bears the advantage not only to detect potential genetic aspects by investigating mice carrying mutations of particular target genes, but also to exploit fundamental causes of depressive-like phenotypes.

Paper presented at Measuring Behavior 2005 , 5^th International Conference on Methods and Techniques in Behavioral Research, 30 August - 2 September 2005, Wageningen, The Netherlands.