Medizinische Universität Graz - Research portal
Selected Publication:
Pauer, J.
Impact of colitis on stress-induced activation of central neurons
Humanmedizin; [ Diplomarbeit ] Medical University of Graz; 2014. pp. 61
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- Authors Med Uni Graz:
- Advisor:
- Holzer Peter
- Reichmann Florian
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- Abstract:
- Background: Stress can aggravate various pathologies including chronic inflammatory and psychiatric disorders. A higher prevalence of anxiety and depressive disorders is documented in patients suffering from inflammatory bowel diseases. Aims: Given this background, the aim of this study was to test the effects of acute stress and colitis on activation of stress-relevant neurons in the mouse brain. Methods: Mice were treated with 2% dextran sulfate sodium (DSS, added to the drinking water) to induce mild colitis, whereas control mice drank normal tap water. After 7 days of treatment, the mice either underwent a 30-minute session of water avoidance stress (WAS) or remained unstressed. Ninety minutes after WAS brains were removed and processed for immunohistochemistry of c-Fos, a marker of neuronal activation. The number of c-Fos expressing cells in brain regions of the limbic system was quantified by computer-assisted cell counting. Results: Stress increased the number of c-Fos expressing cells in the cingulate cortex (P<0.001), the infralimbic cortex (P<0.001), the CA3 region of the hippocampus (P<0.05), the basolateral (P<0.001), central (P<0.001) and medial amygdala (P<0.001) and the paraventricular hypothalamic nucleus (P<0.001) independently of colitis. In the medial amygdala, the stress-induced c-Fos expression in mice with colitis was larger (P<0.001) than in healthy animals (P<0.05). In control animals DSS reduced the number of c-Fos expressing cells in several areas to an insignificant amount. Conclusion: The current experiments show the large impact of stress on central activation and that colitis enhanced stress-evoked stimulation of distinct neurons in the medial amygdala. These results provide functional and neuroanatomical evidence for a distinct interaction of external psychological stressors and internal physical stressors (colitis) in the limbic system of the brain.