Alpha 2-adrenoceptor agonist, dexmedetomidine, protects against kainic acid-induced convulsions and neuronal damage.

Kainic acid (KA)-induced convulsions are accompanied by histopathological changes that are most prominent in the temporal lobe structures. In the present study, we investigated whether a selective alpha2-adrenoceptor agonist, dexmedetomidine could attenuate KA-induced epileptic convulsions and subsequent neuronal damage in the rat hippocampus. Rats were pretreated 30 min before KA injection (9 mg/kg, i.p.) with dexmedetomidine (3 micrograms/kg, s.c.). The behavior of animals was observed for at least 3 h. Dexmedetomidine suppressed the development (p < 0.001), generalization (p < 0.05) and severity (p < 0.01) of convulsions. In addition, histological analysis revealed that dexmedetomidine-treated animals without convulsions or with only partial convulsions had no neuronal damage in the principal cell layers of the hippocampus. A selective alpha2-antagonist, atipamezole (1 mg/kg, s.c.) potentiated KA-induced convulsions and increased the mortality in status epilepticus. In conclusion, the present study demonstrated that dexmedetomidine, in addition to possessing anticonvulsant properties, has a neuroprotective effect in the KA model of status epilepticus.