EFFECT OF AVERSIVE-STIMULATION ON 5-HYDROXYTRYPTAMINE AND DOPAMINE METABOLISM IN THE RAT-BRAIN

The neurochemical consequences of aversive behavior based on novelty, rat social interaction, have been assessed in various rat brain region s utilizing high-performance liquid chromatography coupled with an ele ctrochemical detector (HPLC-ECD) technique. The present studies indica ted that compared to animals from the home cage, those exposed to the high-light aversive unfamiliar test condition had significantly increa sed levels of 5-hydroxyindoleacetic acid (5-HIAA), the metabolite of 5 -hydroxyptryptamine (5-HT), in the tested brain regions including amyg dala, entorhinal cortex, frontal cortex, temporal cortex, tuberculum o lfactorium, hippocampus, nucleus accumbens, and striatum. The levels o f 3, 4-dihydroxyphenylacetic acid (DOPAC) and homovanillic acid (HVA), the metabolites of dopamine (DA), were increased in tuberculum olfact orium, nucleus accumbens, and striatum. When compared to the low-light familiar test condition (LF), the levels, following exposure to the h ighlight unfamiliar situation, of 5-HIAA were significantly increased in the amygdala, entorhinal cortex, tuberculum olfactorium, hippocampu s: and nucleus accumbens, while the 5-HIAA levels remained unchanged i n the frontal cortex, temporal cortex, and striatum. The DOPAC and HVA levels were also increased by the HU situation in the amygdala, tuber culum olfactorium, and nucleus accumbens. An increase was also found f or the levels of DA in the amygdala. Such effects were prevented by di azepam or the 5-HT3 receptor antagonist ondansetron. It is concluded t hat the aversive test condition of the social interaction test (HU) in creases 5-HT and DA turnover throughout the rat brain. Such effects mi ght be related to the sensitivity to novel anxiolytic drug of the soci al interaction test. (C) 1997 Elsevier Science Inc.