The alteration of gamma-aminobutyric acid-transaminase expression in the gerbil hippocampus induced by seizure

It is well established that GABA degradation may play a key role in epilept ogenesis. However, whether or not the expression of GABA-transaminase (GABA -T), which catalyzes GABA degradation and participates in the neuronal meta bolism via GABA shunt, changes chronologically after on-set of seizure rema ins to be clarified. To identify the change of GABA-T expression in seizure , GABA-T expression in the gerbil hippocampus, associated with different se quelae of spontaneous seizures, was investigated. The distribution pattern of GABA-T immunoreactive neurons in the hippocampus between the seizure-res istant and pre-seizure group of seizure sensitive gerbils was similar. Inte restingly, at 30 min postictal, the enhancement of GABA-T immunoreactivity in the perikarya was apparently observed. This contrasted with the decline in GABA-T immunoreactivity in the granular and pyramidal layer. At 12-24 h postictal, GABA-T immunoreactivity in the hilar neurons had declined signif icantly. However, the GABA-T immunoreactivity in the granular layer increas ed. These findings suggest that in the gerbil, the alteration in GABA-T exp ressions may play an important role in the self-recovery mechanism from sei zure attack via both GABA degradation and regulation of neuronal metabolism . (C) 2001 Elsevier Science Ltd. All rights reserved.