Estrogen promotes stress sensitivity in a prefrontal cortex-amygdala pathway.

Area of Science:

• Neuroscience
• Endocrinology
• Cell Biology

Background:

• Stress can induce structural changes in neurons, impacting brain function.
• Previous studies in male rats showed resilience in medial prefrontal cortex (mPFC) to basolateral amygdala (BLA) projecting neurons.
• The role of estrogen in stress-induced neuronal remodeling in females remains less understood.

Purpose of the Study:

• To investigate if mPFC neurons projecting to the BLA in female rats exhibit stress resilience.
• To determine the independent and interactive effects of estrogen and stress on neuronal morphology.

Main Methods:

• Used ovariectomized female rats with and without estrogen replacement.
• Administered immobilization stress or home cage rest for 10 days.
• Utilized retrograde tracing (Fast Blue) and intracellular filling (Lucifer Yellow) to analyze mPFC neurons' dendritic length and spine density.

Main Results:

• Unlabeled neurons showed no stress-induced remodeling, regardless of estrogen status.
• Estrogen replacement in stressed females led to increased dendritic length in BLA-projecting neurons.
• Stress increased spine density in all neurons (without estrogen) and specifically in BLA-projecting neurons (with estrogen).
• Estrogen alone increased spine density in BLA-projecting neurons.

Conclusions:

• Estrogen has independent effects on pyramidal cell morphology.
• Estrogen and stress interact to influence neuronal structure, particularly in mPFC-BLA pathways.
• BLA-projecting neurons in female rats are sensitive to both estrogen's direct effects and its interaction with stress.