Recurrent Early-Life Seizures and Changes in GABAA Receptors Expression in Hippocampus / 소아과

ABSTRACT

The immature brain differs from the adult brain in its susceptibility to seizures, seizure characteristics, and responses to antiepileptic drugs. Gamma(gamma)-aminobutyric acid(GABA) is the predominant inhibitory neurotransmitter in the adult brain. GABA exerts its main action through GABAA receptors, which are coupled to a ligand-gated chloride channel. The receptor protein is a pentameric structure composed of multiple subunits of different families and isoforms. The subunit combinations vary in different brain regions and cell types and determine the functional and pharmacological properties of the receptor. The molecular composition of GABAA receptors is developmentally regulated with associated changes in functional properties. In the developing brain, the delayed onset of functional GABAergic inhibition, and the overabundance of excitatory receptors make the immature brain quite susceptible to seizures. Recurrent seizures in early-life may contribute to seizure susceptibility and epileptogenesis, although the pattern of seizure-induced injury is age-related. The changes of GABAA receptors expression in tetanus toxin-induced seizure model in immature rat hippocampus are different from human temporal lobe epilpsy and experimental model in adult rat. These changes in the immature brain may reflect the induction of compensatory or homeostatic neuronal processes.