Early life stress causes FG-7142-induced corticolimbic dysfunction in adulthood

Area of Science:

• Neuroscience
• Behavioral Neuroscience
• Stress Research

Background:

• Neonatal maternal separation (MS) is a known stressor that increases adult stress responsivity.
• The medial prefrontal cortex (mPFC) and basolateral amygdala (BLA) are key brain regions involved in stress response regulation.
• MS is linked to reduced GABA(A) receptor expression in the mPFC and BLA, but its impact on neuronal function is unclear.

Purpose of the Study:

• To investigate the effects of MS on neuronal activity in the mPFC and BLA.
• To assess how MS alters responses to FG-7142, a benzodiazepine receptor partial inverse agonist that mimics stress effects.

Main Methods:

• Rat pups underwent MS (360 min), handling (H; 15 min), or animal facility rearing (AFR) during early life (postnatal days 2-14).
• In adulthood, in vivo electrophysiology was used to record extracellular unit activity in the mPFC and BLA.
• Neuronal activity was measured under basal conditions and in response to systemic administration of FG-7142.

Main Results:

• Handling (H) increased basal mPFC activity compared to MS and AFR groups.
• MS rats exhibited attenuated mPFC activity in response to FG-7142 compared to H rats.
• MS rats showed potentiated FG-7142-induced BLA activity compared to both H and AFR rats.

Conclusions:

• Neonatal maternal separation induces functionally significant alterations in corticolimbic GABA(A) receptor signaling.
• These findings suggest that early life stress can lead to stress-induced corticolimbic dysfunction, potentially modeling aspects of human stress-related disorders.