Acute cell damage after low Mg2+-induced epileptiform activity in organotypic hippocampal slice cultures

UPON perfusion with Mg2+-free artificial cerebrospinal fluid (ACSF) organot ypic hippocampal slice cultures develop seizure-like events and tonic recur rent discharges in which areas CA3 and CA1 and, in contrast to acute slices , also the dentate gyrus (DG) participate. Using the fluorescent dye propid ium iodide (PI) we show that sustained epileptic activity causes cell death in the DG and pyramidal cell layer particularly evident in the granule cel l layer of the DG. This correlates with the decrease of the electrophysiolo gical responses to hilar stimulation. Interestingly, perfusion with carboge nated serum-free ACSF also induces some cell death which is, however, mild compared with low magnesium treated slice cultures. (C) 1999 Lippincott Wil liams & Wilkins.