Differential brain, but not serum VEGF levels in a genetic rat model of depression

Compared to the classical monoamine hypotheses focus on neuroplasticity is a major new approach in studies of depression and antidepressants. Recent studies have demonstrated that vascular endothelial growth factor (VEGF) is regulated by antidepressant treatment in rodents. However, in depressive patients no significant changes were found in the serum VEGF levels compared to control subjects. To our knowledge, brain and serum VEGF levels have never been reported in parallel for any psychiatric disease model. That prompted us to examine the levels of VEGF in serum, hippocampus, frontal cortex, corpus striatum, and hypothalamus in male Flinders Sensitive Line (FSL) and Flinders Resistant Line (FRL), a genetic rat model of depression. The VEGF levels were identical in the FSL and the FRL rats in serum, corpus striatum, and hypothalamus. In hippocampus and frontal cortex, the VEGF levels were significantly decreased in the FSL rats compared to the FRL rats. The results may add to the hypothesis that altered expression of growth factors/neurotrophic factors are related to the pathophysiology of depression.