Dysfunction of synaptic neurotransmitter release is closely involved in the pathogenesis of
various central nervous system diseases. Synaptic vesicle glycoprotein 2A (SV2A) is a membrane protein
specifically expressed in synaptic vesicles and it modulates action potential-dependent neurotransmitter
release in the brain. Since 1) SV2A-knockout mice exhibit severe convulsive seizures, 2)
SV2A expression in the brain is reportedly altered in various epileptic disorders both in animal models
(e.g., kindling and genetic models) and humans (e.g., intractable temporal lobe epilepsy and focal cortical
dysplasia) and 3) SV2A serves as a specific binding site for the antiepileptic drug, levetiracetam
and its analogues, it is considered that SV2A is involved in the pathogenesis and treatment of epilepsy.
In addition, a recent clinical study demonstrated that a missense mutation in the SV2A gene caused intractable
epilepsy with involuntary movements and developmental retardation, illustrating a causative
role of SV2A dysfunction in epilepsy. Although the functional mechanisms of SV2A in regulating epileptogenesis
remain unknown, studies using animals carrying the Sv2a missense mutation showed that
the dysfunction of SV2A preferentially disrupts action potential-induced γ-aminiobutyric acid
(GABA), but not glutamate, released in the limbic regions (i.e., hippocampus and amygdala) and
markedly facilitates kindling epileptogenesis. All these evidences indicate that the SV2A-GABAergic
system plays a crucial role in modulating epileptogenesis and encourages research on the novel antiepileptic
agents which enhance SV2A function.
Keywords: Antiepileptic drugs, epilepsy, epileptogenesis, γ-aminiobutyric acid, glutamate, neurotransmitter release, synaptic
vesicle glycoprotein 2A.
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