Study On The Relation Between Serotonin,Glutamate,Nitric Oxide In Orbitofrontal Cortex And Stress-induced Depression

Depression is a mental disorder especially with low spirits. Stress is an unspecific adaptive response when animals are confronted with various stimulus. Social stress such as the quickened social rhythm, increasingly furied work competition, make people have more and more mental burdens. Stressful life events have high affinity to depression, this suggests that the social stress could be important in the pathogenesis of some depressive disorders.Among numerous studies for mechanism and antidepressant filtration, stressful model is the most universal one conducted to indicate psychobiology and psyhoparmacology of depression. But the mechanism between different brain sites, neurotransmitters and depression under stressful state has not been firmly established. Orbitofrontal cortex is a brain site which has close relation to emotion, recent researches clue to its possible effect in depression.We select male SD rats, adopt forced swimming test to construct animal depression model, microinject drugs into OFC, and OFT,FST to test behavior. We also use immunohistochemistry to observe c-fos,5-HT_1A receptor expression in OFC and related brain areas. We primarily discussed the relation between different neurotransmitters during the depression pathology in OFC area and forced swimming stress. The results are as follows:1.Activity changes of c-fos expression in different brain areas during stress(n=5): after forced swimming test, stressed rats have more positive expression of c-fos in OFC, hippocampus, PVN, ME and so on when compared with control group.2.Analysis of the relation between serotonin and its receptor in OFC and stress depression(n=8): (1) Microinjection of 5-HT into OFC significantly shortened immobility time, dejections have no great changes; though locomotor, grooming activitives have little increased, they have no significant difference; rearing scores greatly reduced; (2)microinjection of pCPA into OFC significantly prolong immobility time, dejections have no great changes; locomotor,rearing activities are greatly reduced, but have no significant effect on grooming activity receding; (3)compared with the effect of 5-HT alone, microinjection of spiperone combined with 5-HT into OFC, significantly prolong immobility time and greatly reduced dejections; locomotor, rearing, grooming activities are all reduced, but have no significant differences.3.Influences of forced swimming stress on brain 5-HT_1A receptor numbers(n=8): after...