Seletracetam enhances short term depression in vitro

Area of Science:

• Neuroscience
• Pharmacology
• Epilepsy Research

Background:

• Seletracetam (SEL) is an analog of levetiracetam (LEV), an established antiepileptic drug.
• SEL exhibits higher binding affinity to the synaptic vesicle protein SV2A compared to LEV.
• Previous studies indicate LEV reduces seizure activity and affects synaptic transmission.

Purpose of the Study:

• To investigate if SEL, like LEV, reduces synaptic potentials in response to high-frequency stimulation.
• To determine if SEL's effect is dependent on SV2A binding and access to synaptic vesicles.
• To explore the potential of SV2A as a therapeutic target for epilepsy.

Main Methods:

• Experiments utilized hippocampal slices from epilepsy models.
• Slices were incubated with varying concentrations and durations of SEL.
• Synaptic transmission was assessed using field excitatory synaptic potentials (fEPSPs) and FM1-43 imaging of synaptic boutons.

Main Results:

• SEL (3-30μM, 3h incubation) significantly decreased CA1 fEPSP amplitude during high-frequency stimulation.
• This short-term depression was frequency and dose-dependent and required access to synaptic vesicles.
• SEL loading slowed FM1-43 release from synaptic boutons, indicating impaired vesicle recycling.

Conclusions:

• Seletracetam (SEL) induces a frequency-dependent decrement in synaptic transmission, similar to levetiracetam (LEV).
• The observed effect is contingent upon SEL entering recycling synaptic vesicles and binding to SV2A.
• SV2A represents a promising target for the development of new antiepileptic drugs.