Mitochondrial complex I inhibition produces selective damage to hippocampal subfield CA1 in organotypic slice cultures

The effects of mitochondrial respiratory chain inhibitors and the excitotoxinN-methyl-D-aspartate (NMDA) on cell death in hippocampal subfields CA1 and CA3 were examined in hippocampal organotypic slice cultures. Slice cultures, 2–3 week old, were exposed for 1 h to either the Complex 1 inhibitors, rotenone or 1-methyl-4-phenylpyridium (MPP⁺), the Complex II inhibitor 3-nitropropionic acid (3-NP), or the excitotoxin NMDA. Cell death was examined 24 and 48 h following treatment, by measuring propidium iodide (PI) fluorescence. Treatment with 1 μM rotenone caused greater cell death in hippocampal subfield CA1 than CA3. Exposure of hippocampal slice cultures to 10 μM rotenone, to MPP⁺ or to NMDA resulted in damage to both CA1 and CA3 subfields. 3-NP produced little damage in either subfield. The data suggest that mitochondrial complex I inhibition can produce selective cell damage in hippocampus and in this regard is similar to that observed following hypoxia/ischemia.