Pregabalin Depresses Cerebellar Parallel Fiber-Purkinje Cell Synaptic Transmission by Modulating Glun2a-Containing...

Area of Science:

• Neuroscience
• Pharmacology
• Cellular Biology

Background:

• Pregabalin (PGB) targets α2δ subunits of voltage-gated calcium channels, modulating brain synaptic transmission.
• The specific impact of PGB on cerebellar parallel fiber-Purkinje cell (PF-PC) synaptic transmission is not well understood.

Purpose of the Study:

• To investigate the effects of PGB on PF-PC synaptic transmission in the mouse cerebellar cortex.
• To elucidate the underlying molecular mechanisms, including the roles of N-methyl-D-aspartate receptors (NMDARs) and protein kinase A (PKA).

Main Methods:

• Whole-cell patch-clamp recording to measure synaptic currents.
• Glutamate fluorescence imaging to assess neurotransmitter release.
• Immunohistochemistry, co-immunoprecipitation, and Western blotting to analyze protein interactions and signaling pathways.
• Pharmacological approaches using receptor blockers and kinase inhibitors.

Main Results:

• PGB concentration-dependently inhibited PF-PC excitatory postsynaptic currents (EPSCs) and increased the paired-pulse ratio, indicating reduced presynaptic release.
• PGB reduced evoked glutamate release and the frequency of miniature EPSCs (mEPSCs) without altering their amplitude.
• These effects were abolished by extracellular blockade of GluN2A-containing NMDARs or disruption of α2δ-1-NMDAR complexes, and by extracellular PKA inhibition.
• PGB increased PKA phosphorylation in the cerebellar molecular layer, and α2δ-1 and GluN2A subunits were found to be co-localized and interacting.

Conclusions:

• PGB depresses glutamate release from parallel-fiber terminals in the mouse cerebellum.
• This occurs through a presynaptic mechanism involving α2δ-1-coupled GluN2A-containing NMDARs and the PKA signaling pathway.
• PGB attenuates PF-PC synaptic transmission via this novel presynaptic pathway.