HYPEREXCITABILITY AND CELL LOSS IN KAINATE-TREATED HIPPOCAMPAL SLICE CULTURES

Loss of hippocampal interneurons has been reported in patients with se vere temporal lobe epilepsy and in animals treated with kainate. We in vestigated the relationship between KA induced epileptiform discharge and loss of interneurons in hippocampal slice cultures. Application of KA (1 mu M) produced reversible epileptiform discharge without neurot oxicity. KA (5 mu M), in contrast, produced irreversible epileptiform discharge and neurotoxicity, suggesting that the irreversible epilepti form discharge was required for the neuronal loss. Loss of CA3 pyramid al cells and parvalbumin-like immunoreactive (PV-I) interneurons prece ded loss of somatostatin-like immunoreactive (SS-I) interneurons sugge sting a different time course of KA neurotoxicity in these subpopulati ons of interneurons.