Changed vesicular GABA transporter immunoreactivity in the gerbil hippocampus following spontaneous seizure and vigabatrin administration

To identify the roles of vesicular gamma-aminobutyric acid (GABA) transporter (VGAT) in epileptogenesis and the recovery mechanisms in spontaneous seizure, we conducted a chronological and comparative analysis of VGAT expression. VGAT immunoreactivity was stronger in the seizure resistant group than that in the pre-seizure group of seizure sensitive (SS) gerbils. In 3 h postictal group, the density of VGAT immunoreactivity was significantly increased in the hippocampus, as compared to pre-seizure group. In 24 h postictal group, VGAT immunodensity had recovered to its pre-seizure level. In addition, VGAT immunoreactivity in the hippocampus was also increased by vigabatrin (GVG) administration. These results suggest that decreased VGAT expression in the SS gerbil hippocampus may affect epileptogenesis in this animal, and that the subsequent alteration in its expression induced by seizure and the administration of GVG may reflect a modulation of GABA release to alleviate seizure activity.