Enduring Efffects Of Juvenile Fluoxetine Exposure On Serotonin Transporter Expression Within The Hippocampus And Prefrontal Cortex Of Male C57bl/6 Mice

Prescription rates of fluoxetine, the most dispensed selective serotonin reuptake inhibitor, have been rising among the juvenile population. Since adolescence is a critical developmental period in which the brain undergoes pruning, chronic increases in serotonin levels may lead to long-term neurobiological changes in brain regions responsible for emotional regulation. Thus, using mice as a model system, this thesis evaluated how adolescent fluoxetine exposure (AFE) influences the expression of serotonin transporters (SERT) in the adult hippocampus and prefrontal cortex. To do this, postnatal day (PD)-35 male C57BL/6 mice were administered with fluoxetine (250 mg/l in their drinking water) for 15 consecutive days (PD35-49). Three weeks later, when mice reached adulthood (PD70), bilateral hippocampus and prefrontal cortex brain tissue was dissected and analyzed for SERT protein expression, adopting the Western immunoblot technique. The results indicated that, when compared to controls, adult mice with AFE-history exhibited increased SERT protein expression in the hippocampus. In contrast, expression of SERTs was decreased in the prefrontal cortex as a function of AFE. Collectively, the data suggest that persistent fluoxetine-induced brain region-specific changes in SERT expression are evident in adulthood when exposed to this antidepressant medication during the adolescent stage of development.