Regional excitatory and inhibitory amino acid concentrations in Noda epileptic rat (NER) brain

We measured regional concentrations of excitatory and inhibitory amino acids in Noda epileptic rat (NER) brains to investigate the mechanisms responsible for spontaneous generalized seizures. Compared with Fisher 344 (F344) rats and F1 hybrid (female NER×male F344 rat) rats, NERs had significantly higher concentrations of glycine in the cerebellum. NERs and F1 hybrid rats had significantly lower concentrations of taurine in the cerebellum than did F344 rats. Although our findings do not explain sufficiently the mechanisms directly responsible for spontaneous seizures, they suggest that the cerebellum of NER may be in an excited state to dampen seizures, while the cerebellum of F1 hybrid rats may also be slightly excited to inhibit milder forms of seizures. Further studies, including microdialysis and receptor binding assays, will be required to elucidate these mechanisms.