Resistance to epileptic, but not anoxic, depolarization in the gerbil hippocampal slice preparation

The Mongolian gerbil displays spontaneous seizures and is used as a model for global ischemia. This study investigated the electrophysiological events associated with 0-Mg(2+)-induced seizures in gerbil hippocampal slices. In the rat hippocampal slice, 0-Mg2+ medium leads to rapid extracellular epileptic depolarization (ED) accompanied by long-term synaptic failure. Both evoked and spontaneous epileptiform activity was observed in the gerbil hippocampal slice after the introduction of the 0-Mg2+ aCSF. However, unlike the rat, ED was rarely observed in the gerbil hippocampal slice (2/17). When ED occurred, synaptic responses recovered (75%) within 20 min. This resistance to epileptic depolarization did not generalize to experimental ischemia-induced depolarization. Anoxia in 2 mM D-glucose produced anoxic depolarization in all gerbil hippocampal slices tested (6/6).