BACKGROUND: The present investigation was undertaken to evaluate the neuroprotective effect of etomidate against kainic acid (KA) induced neurotoxicity in rats by Western immunoblotting for heat shock protein 70 (HSP-70), c-JUN, and by acid-fuchsin histochemistry.

METHODS: Etomidate (20 mg/kg, i.p.) was administered in sequence, first being just one hour after KA (10 mg/kg, i.p.) injection, then three times one hour intervals. Neuronal damage in hippocampus was evaluated by using acid-fuchsin stain to detect cell death and HSP-70 and c-JUN induction as an index of cell injury at 3, 6, 24 and 48 h after the administration of KA.

RESULTS: Acid fuchsin positive neurons were increased in the CA1 and CA3 regions of the hippocampus after KA injection, but were significantly decreased by etomidate injection (P < 0.01). Etomidate administration also significantly suppressed the KA-induced induction of c-JUN and HSP-70 in both regions of the rat hippocampus.

CONCLUSIONS: These results suggest that etomidate has a protective effect on hippocampal neurons against KA-induced neurotoxicity.