ENVIRONMENTAL INFLUENCE ON SOMATOSTATIN LEVELS AND GENE-EXPRESSION INTHE RAT-BRAIN

In the present study we have quantified preprosomatostatin-mRNA and so matostatin levels in rat brain following environmental stimulation. An imals were housed for 30 days in an enriched or impoverished environme nt prior to analysis. After 30 days of housing half of the rats from e ach environment were behaviourally tested for 3 days. Housing in enric hed environment improved performance in a spatial learning situation. The open-field behaviour of these animals was characterized by initial ly higher rearing scores and a more rapid habituation to novel environ ment as measured by spontaneous locomotor activity. We found significa ntly elevated somatostatin levels in the cortex following enriched env ironment, compared with impoverished environment. Exposure to behaviou ral testing of impoverished animals led to increased cortical somatost atin levels. Hypothalamic somatostatin levels increased significantly after housing in enriched environment. while the testing procedure had no influence. Our data shows that the somatostatin system in the rat brain was activated in association with cognitive changes, that were i nduced by housing in an enriched environment.