[Effects of fluoxetine on locomotor activity: possible involvement of dopamine].

Plus-maze benavior of adult mail rats was assessed and contents of 5-hydroxyindoleacetic acid (5-HIAA) and dopamine (DA) in different brain regions were analyzed after two-week fluoxetine treatment (25 mg/kg/day, per os). Chronic fluoxetine treatment produced a general decrease in the brain 5-HIAA content and a decrease in DA content in the frontal cortex and striatum. Behaviorally, fluoxetine-treated animals displayed enhanced anxiety and decreased locomotor activity. The DA depletion os supposed to be responsible for fluoxetine-produced hypolocomotion. This is supported by a significant correlation between the dopamine content in the frontal cortex and the number of entries into the closed arms of the plus-maze. The results suggest that the hypolocomotor effect of fluoxetine may involve the changes in the dopaminergic system.