Glutamate-dependent long-term presynaptic changes in corticostriatal excitability

Area of Science:

• Neuroscience
• Neurophysiology
• Synaptic Plasticity

Background:

• Previous research demonstrated that high-frequency stimulation decreases corticostriatal excitability.
• Dual stimulation protocols can induce long-term increases in presynaptic corticostriatal excitability.

Purpose of the Study:

• To investigate the specific glutamate receptor subtypes mediating long-term changes in presynaptic corticostriatal excitability.
• To differentiate the roles of N-methyl-D-aspartate (NMDA), metabotropic glutamate (mGluR), and alpha-amino-3-hydroxy-5-methylisoxazole-4-propionic acid (AMPA)/kainate receptors.

Main Methods:

• Infusion of glutamate receptor antagonists into the rat striatum prior to cortical tetanic stimulation.
• Utilized kainic acid lesions to eliminate intrinsic striatal cell involvement.
• Examined long-term changes in presynaptic excitability following single and double stimulation protocols.

Main Results:

• NMDA and mGluR antagonists blocked the excitability decrease induced by single stimulation.
• AMPA/kainate receptor antagonists did not prevent the long-term excitability reduction.
• All tested antagonists prevented the induction of long-term excitability increases.

Conclusions:

• Long-term modifications in presynaptic excitability involve distinct glutamate receptor mechanisms.
• These plasticity mechanisms are analogous to those in long-term potentiation and depression.
• Enduring changes in presynaptic excitability are crucial for selective information processing in the striatum.