Serotonin and corticosterone-neurochemical indicators of sterss
The anxiety tests are widely used to study behaviour of rats in the stress-inducing situation. The study presents a comparative analysis of the infl uence of different stressogenic stimuli on the serotonergic activity in the emotional brain regions and on plasma corticosterone concentration in rats. The animals were subject to two various behavioral tests, and subsequently the concentration of serotonin (5- HT), its metabolite 5 – hydroxyindoleacetic acid (5-HIAA) and of plasma corticosterone concentration were determined using highperformance liquid chromatography with electrochemical detection (HPLC-ED). Stressogenic stimuli in the tests performed were: light of high volume (light dark transition test – LDT) or open fi eld (open fi eld test – OF). HPLC-ED analysis showed a signifi cant increased of 5-HT level in the amygdala (AM) after using both tests. HPLCED analysis showed also an increased of 5-HIAA concentration in the frontal cortex (CTX), in the hippocampus (HI), in the AM after using the LDT-test and an increased of 5-HIAA concentration in the CTX and in the AM after using OF-test. Simultaneously, the analysis showed elevation of corticosterone concentration in rats exposed to LDT and OF. These results confi rm that serotonin and coricosterone participate in the regulation of emotional response and they are important neurochemical indicators of stress.