Brain region specific monoamine and oxidative changes during restraint stress

Background and Purpose: Stress-induced central effects are regulated by brain neurotransmitters, glucocorticoids and oxidative processes. Therefore, we aimed to evaluate the simultaneous alterations in the monoamine and antioxidant systems in selected brain regions (frontal cortex, striatum and hippocampus) at 1 hour (h) and 24h following the exposure of restraint stress (RS), to understand their initial response and possible crosstalk. Methods and Results: RS (150 min immobilization) significantly increased the dopamine levels in the frontal cortex and decreased them in the striatum and hippocampus, with selective increase of dopamine metabolites both in the 1h and 24h RS groups compared to control values. The serotonin and its metabolite levels were significantly increased in both time intervals, while noradrenaline levels were decreased in the frontal cortex and striatum only. The activities of superoxide dismutase, glutathione peroxidase and the levels of lipid peroxidation were significantly increased with significant decrease of glutathione levels in the frontal cortex and striatum both in the 1h and 24h RS groups. There was no significant change in the catalase activity in any group. In the hippocampus, the glutathione levels were significantly decreased only in the 1h RS group. Conclusions: Our study implies that the frontal cortex and striatum are more sensitive to oxidative burden which could be related to the parallel monoamine perturbations. This provides a rational look into the simultaneous compensatory central mechanisms operating during acute stress responses which are particular to precise brain regions and may have long lasting effects on various neuropathological alterations.