Effects of Environmental Enrichment on Behavioral Deficits, Cognitive Impairment and Alteration in BDNF Level Induced by Postnatal Serotonin Depletion in Adult Male Rats

The neurotransmitter serotonin (5-HT) has a critical role in neural development and functions. Previous studies indicated that changes in serotonergic system signaling in early life critically impact mental health, behavior, and brain function across the life span. Therefore, the present study was aimed to evaluate the influences of the enriched environment (EE) housing (Postnatal day: PND21-60) following postnatal (PND 10–20) serotonin depletion by para-chlorophenylalanine (PCPA, 100mg/kg, s.c) administration on anxiety-related behaviors, passive avoidance performance, and brain-derived neurotrophic factor (BDNF) mRNA expression in the hippocampus of adult male rats. Memory and behavioral parameters were examined in early adulthood (PND60-70) and after that, the hippocampi of rats were removed under deep anesthesia to determine the BDNF mRNA expression by PCR. The findings of the present work indicated that adolescent EE exposure alleviated the memory impairment, decreased BDNF level, and anxiety disorders induced by experimental depletion of serotonin. Overall, these results indicate that serotonergic system dysregulation during the developmental periods can compensate by adolescent EE exposure.Ethics: All procedures in the present study were approved by the Ardabil University of Medical Sciences Ethics Committee, which is in accordance with the "National Institute of Health NIH Guide to the Care and Use of Laboratory Animals"Competing interests: NoneFunding: Ardabil university of medical sciences , financially supported our mentioned study(IR.ARUMS.REC.1399.008 )