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

Upon perfusion with Mg2+-free artificial cerebrospinal fluid (ACSF) organotypic hippocampal slice cultures develop seizure-like events and tonic recurrent discharges in which areas CA3 and CA1 and, in contrast to acute slices, also the dentate gyrus (DG) participate. Using the fluorescent dye propidium iodide (PI) we show that sustained epileptic activity causes cell death in the DG and pyramidal cell layer particularly evident in the granule cell layer of the DG. This correlates with the decrease of the electrophysiological responses to hilar stimulation. Interestingly, perfusion with carbogenated serum-free ACSF also induces some cell death which is, however, mild compared with low magnesium treated slice cultures.