NMDA receptor-dependent metaplasticity by high-frequency magnetic stimulation

Area of Science:

• Neuroscience
• Synaptic Plasticity
• Electrophysiology

Background:

• High-frequency magnetic stimulation (HFMS) can induce N-methyl-D-aspartate (NMDA) receptor-dependent long-term potentiation (LTP).
• Understanding metaplasticity, the modulation of subsequent synaptic plasticity, is crucial for comprehending learning and memory.

Purpose of the Study:

• To investigate the priming effect of HFMS on electrically induced LTP in rat hippocampal CA1 synapses.
• To determine the receptor mechanisms underlying HFMS-induced metaplasticity.

Main Methods:

• Field excitatory postsynaptic potential (fEPSP) recordings were used in rat hippocampal slices.
• Electrical high-frequency conditioning stimulation (CS) was applied to induce LTP.
• HFMS was delivered 30 minutes prior to CS, with and without receptor antagonists.

Main Results:

• HFMS priming significantly reduced the magnitude of subsequent electrically induced LTP.
• This priming effect was attenuated by metabotropic glutamate receptor antagonists (MSOP and MCPG).
• NMDA receptor antagonism during HFMS prevented the reduction in LTP, restoring it to control levels.

Conclusions:

• HFMS induces metaplasticity by reducing the capacity for subsequent LTP.
• Both NMDA and metabotropic glutamate receptors play critical roles in mediating HFMS-induced metaplasticity.