WATER-IMMERSION RESTRAINT STRESS AND SEROTONERGIC MEASURES IN BLOOD AND DIFFERENT AREAS OF RAT-BRAIN

The effects of water-immersion restraint stress on the concentration o f serotonin (5-HT), 5-hydroxyindoleacetic acid (5-HIAA) and tryptophan in blood and different parts of brain have been studied. After 1 h st ress a significant rise in blood 5HIAA was observed whereas 5-HT and t ryptohan levels remained unaffected. 5-HT level was found to be increa sed in striatum, midbrain, hippocampus and cortex compared to the cont rol group. In two latter brain areas a concomitant rise in 5-HIAA was observed. In medulla and hypothalamus 5-HIAA concentration decreased f ollowing stress. 5-HIAA/5-HT ratio was significantly lower in medulla, hypothalamus and midbrain compared to the control group. Tryptophan l evels remained unchanged except hypothalamus. Our data suggest a compl ex influence of stress upon different types of central serotonergic ne urons.