The effects of prolonged dexamethasone treatment and single MRI procedure under anesthesia on hippocampal and prefrontal cortex volume in rats
Landgraf R, Auer D, Almeida O, Wigger A, Hemauer R, Schubert M, Kalisch R
Max Planck Institute of Psychiatry
Hippocampal volume loss in humans and rodents supposedly results from elevated glucocorticoids. To further investigate structural changes in limbic system, i.e. hippocampus, anterior cingulate and retrosplenial cortex, non-adrenalectomized rats with and without long-term dexamethasone treatment were examined by in vivo MR-morphometry at 7T. No hippocampal volume loss was found in dexamethasone treated rats. Unexpectedly, the procedure itself led to reduced ACC and RSG both in untreated and dexamethasone treated rats. This study further questions the validity of the assumed dexamethasone-induced MRI detectable HV loss, but suggests extrahippocampal brain plasticity in response to a single stressful event in conjunction with anesthesia.