6 fold. In situ hybridization showed also specific expression of APP in the PVN. Finally, to test whether stress regulation click here of GNAi2 and APP is specific to the PVN, we also analysed the hypothalamic region just anterior and posterior to the PVN. The results show no significant change in the expression levels of GNAi2 and APP for the respective time point. Clustering analysis of GNAi2 APP Having corroborated a potential role of the GNAi2 APP connection in stress response of DBA mice, we used clustering analysis to identify genes that display similar expression changes throughout the conditions we analysed. In setting up the clustering analysis, we considered both up and down regulation, because some transcriptional regulators, such as GR, are able to both up and down regulate genes.

Genes identified in a clus tering analysis may be under a common transcriptional control, or influencing each other. The dendrograms revealed 10 and 15 genes for GNAi2 and 12 for APP. Several genes with known function were among these nearest neighbours. To test potential, already described connections between these genes, we again used a pathway building program. Interestingly, we found that GNAi2 is located in a signalling cascade, where Heart and neural crest derivatives expressed transcript 2 is upstream, APP is downstream and MAP3K2 further downstream. DHDDS and GNAi2 share a common upstream regulator as well as a common downstream target. GNAi2 and COPS5 have a common target as well. In addition, GNAi2 and APP are found both downstream of another common regulator.

Furthermore, for APP we identified common upstream regulators with PAPOLA, EN1 as its regulator and HSD17B4 as its target. Interestingly, DGKZ and APP are linked in a feedback loop. Thus, the clustering analysis revealed functionally related genes, indeed. Discussion The PVN of the hypothalamus is pivotal in governing physiological stress response. We examined the impact of forced swimming as an acute stressor on gene expres sion in the PVN of C57BL 6 and DBA 2J mice. These inbred mouse strains have been used as a genetic animal model of depression like behaviour and are character ized by a different stress responsiveness, since DBA 2J mice display a stronger behavioural response to stressful conditions. We discovered that the stress regulated genes code mainly for receptors and signal transduction molecules, as well as numerous biosyn thetic molecules. Cilengitide This result is consistent with a pre vious study of gene expression profiling in the hypothalamus of mice stressed by immobilization, where genes involved in energy and lipid metabolism, apopto sis, signal transduction, DNA repair, protein biosynth esis, and structure integrity related genes were found.