Mild prenatal stress-modulated behavior and neuronal spine density without affecting amphetamine sensitization

Area of Science:

• Neuroscience
• Behavioral Neuroscience
• Developmental Neuroscience

Background:

• Prenatal stress (PS) is a significant environmental factor impacting neurodevelopment and behavior.
• Understanding the long-term effects of PS on brain structure and drug responses is crucial for addressing potential mental health issues.

Purpose of the Study:

• To investigate the effects of prenatal stress on juvenile behavior and adult amphetamine sensitization in rats.
• To examine the interaction between prenatal stress and amphetamine on cortical thickness and neuronal morphology in corticolimbic regions.
• To assess the impact of prenatal stress on spine density in the nucleus accumbens, medial prefrontal cortex, and orbital frontal cortex.

Main Methods:

• Exposure of juvenile male and female rats to gestational stress.
• Behavioral testing including open field locomotion, elevated plus maze, novel object recognition, and play fighting.
• Assessment of amphetamine (AMPH)-induced behavioral sensitization through chronic administration and challenge.
• Examination of spine density in corticolimbic regions (nucleus accumbens, medial prefrontal cortex, orbital frontal cortex) for structural plasticity.

Main Results:

• Prenatal stress induced anxiety-like behavior in male rats and altered play fighting behaviors in both sexes.
• Amphetamine administration led to persistent behavioral sensitization, but prenatal stress did not influence this sensitization.
• Prenatal stress altered spine density in the nucleus accumbens and medial prefrontal cortex, and prevented drug-induced changes in spine density in these regions.

Conclusions:

• Prenatal stress significantly modulates juvenile behavior and induces lasting changes in brain morphology, particularly in corticolimbic regions.
• Despite alterations in neuroplasticity, prenatal stress does not substantially affect the development or persistence of amphetamine-induced behavioral sensitization.
• These findings highlight the complex interplay between early-life stress, brain development, and drug-induced behavioral responses.