Long-lasting monoaminergic and behavioral dysfunctions in a mice model of socio-environmental stress during adolescence

• Stress during adolescence compromises the capacity of the HPA axis ability to properly respond to a stressor in adulthood.
• Socio-environmental stress during adolescence causes non-adaptive rearrangement in the CNS.
• Long-lasting changes in neural pathways and behavior in stressed adolescent male mice.

Adolescence is one of the critical periods of development and has great importance to health for an individual as an adult. Stressors or traumatic events during this period are associated with several psychiatric disorders as related to anxiety or depression and cognitive impairments, but whether negative experiences continue to hinder individuals as they age is not as well understood. We determined how stress during adolescence affects behavior and neurochemistry in adulthood. Using an unpredictable paradigm (2 stressors per day for 10 days) in Balb/c mice, behavioral, hormonal, and neurochemical changes were identified 20 days after the cessation of treatment. Adolescent stress increased motor activity, emotional arousal and vigilance, together with a reduction in anxiety, and also affected recognition memory. Furthermore, decreased serotonergic activity on hippocampus, hypothalamus and cortex, decreased noradrenergic activity on hippocampus and hypothalamus, and increased the turnover of dopamine in cortex. These data suggest behavioral phenotypes associated with emotional arousal, but not depression, emerge after cessation of stress and remain in adulthood. Social-environmental stress can induce marked and long-lasting changes in HPA resulting from monoaminergic neurotransmission, mainly 5-HT activity.