Corticosterone alters AMPAR mobility and facilitates bidirectional synaptic plasticity.

Area of Science:

• Neuroscience
• Molecular Biology
• Endocrinology

Background:

• Corticosterone, a stress hormone, exhibits bidirectional effects on synaptic plasticity, learning, and memory.
• The precise molecular mechanisms behind these effects remain largely unknown.
• AMPA receptors are crucial for activity-dependent plasticity and hippocampal learning.

Purpose of the Study:

• To investigate the relationship between corticosterone and AMPA receptors.
• To elucidate the molecular underpinnings of corticosterone's impact on synaptic efficacy.

Main Methods:

• Immunocytochemistry and live cell imaging in primary hippocampal cultures.
• Analysis of AMPA receptor subunit GluR2 surface expression and lateral diffusion.
• Investigation of NMDAR-mediated endocytosis.

Main Results:

• Corticosterone selectively increases surface expression of the AMPA receptor subunit GluR2.
• This increase is dependent on glucocorticoid receptors and protein synthesis.
• Corticosterone enhances lateral diffusion of surface GluR2 and facilitates its endocytosis, potentially weakening synaptic transmission.

Conclusions:

• Corticosterone increases mobile GluR2-containing AMPA receptors.
• Enhanced lateral diffusion can facilitate AMPA receptor recruitment or loss (LTD).
• These actions may explain the dual effects of corticosteroids on synaptic plasticity and learning/memory.