Stress, depression and hippocampal apoptosis

Area of Science:

• Neuroscience
• Cell Biology
• Psychiatry

Background:

• The mammalian hippocampus, particularly the dentate gyrus (DG), exhibits ongoing apoptosis, albeit at low levels.
• Stress and steroid exposure are known to influence the rate of apoptosis in the DG.

Purpose of the Study:

• To review and discuss recent research on structural plasticity, focusing on apoptosis in the hippocampus.
• To examine the effects of stress and depression on hippocampal structural changes and their functional implications.

Main Methods:

• Review of recent studies on structural plasticity, apoptosis, and stress in the mammalian hippocampus.
• Analysis of the impact of chronic stress on hippocampal cell number, volume, synaptic structure, and dendritic arborization.

Main Results:

• Chronic stress leads to modest, often transient, structural changes in the hippocampus (<10% reduction in cell number/volume) requiring severe exposure.
• Apoptosis and proliferation rates in the DG are temporarily slowed by chronic stress, affecting DG cell composition and hippocampal circuit properties.
• Structural changes are generally reversible upon cessation of stress or corticosteroid exposure.

Conclusions:

• While hippocampal structural changes from stress are modest, they can significantly impact memory function.
• Modulating apoptosis and neurogenesis via drugs targeting stress pathways (MR, GR) presents potential therapeutic targets for mood and memory disorders.