SUBICULUM, PRESUBICULUM AND PARASUBICULUM HAVE DIFFERENT SENSITIVITIES TO SEIZURE-INDUCED NEURONAL DAMAGE IN THE RAT

The extent and severity of neuronal damage in the subiculum, presubicu lum and parasubiculum were studied in 2 experimental models of status epilepticus. Seizures were induced either by electrical stimulation of the perforant pathway or by systemic injection of kainic acid. Neuron al damage was analyzed from sections stained with thionin or Gallyas s ilver impregnation 2 days and/or 2 weeks after the induction of seizur es. The principal cell layer of the subiculum was severely damaged onl y in the kainic acid model. In both seizure models, the presubiculum w as well preserved. On the other hand, in both models, layers TI and II I of the parasubiculum were damaged. The present study suggests that t he neurons in the subiculum, presubiculum and parasubiculum have diffe rent sensitivities to epileptic neuronal damage, which may alter the e pileptogenicity of the temporal lobe neuronal network.