Leiden/Amsterdam Center for Drug Research, Department of Medical Pharmacology, University of Leiden, Leiden, The Netherlands
To use behavior as a means to elucidate mechanisms and processes of homeostatic control, behavioral methodology must be embedded in experimental settings incorporating the knowledge derived from other disciplines of (neural) sciences. An example of this approach is the elucidation of the role of corticosteroid hormones in behavior. Corticosteroids are related to behavioral adaptation restoring homeostasis and information processing is closely linked to the hippocampus. The high density and colocalization of mineraloreceptors (MR) and glucocorticoid receptors (GR) in the hippocampus, and the stabilizing effect of MR and GR activation on neuronal excitability emphasize their important role in the regulation of the hippocampal formation. Behavior specifically related to hippocampal functioning requiring spatiotemporal coordination represents the means to elucidate the role of corticosteroids in information processing.
Different training and free swim trial schedules in the Morris water maze task, genetically determined variations in the steroid system (rat lines, transgenic mice) and pharmacological interventions resulted in experimental designs which allowed - in combination with the image analysis system EthoVision - to unravel the specific effects of corticosteroids mediated by MR and GR. We demonstrated that corticosteroids present a hormonal signal that influences the processing of information in an organising and synchronising fashion due to its differential MR- and GR-mediated actions. It is the integrative design of the experiment supported by the automated registration and analysis of the behavior which bring us one step further in our understanding of the mechanisms underlying behavior.
Reference
Oitzl, M.S. (1995). Behavioral approaches to study function of corticosteroids in brain. In E.R. de Kloet and W. Sutanto (eds.). Methods in Neurosciences. Neurobiology of Steroids. Academic Press, New York, pp. 483-495.
Supported by NWO grant 903-54-545.