The induction of c-fos protein-like immunoreactivity (CFPLI) was examined in the hippocampus of gerbils at several time points after transient global ischemia. c-Fos protein induction was largely confined to the dentate gyrus, CA3 and CA4 regions from 2 to 8 h after transient bilateral carotid occlusion. Little CFPLI was seen in the CA1 subfield, which is disproportionately sensitive to injury after global ischemia. c-Fos induction was completely blocked by pretreatment with MK-801 (3 mg/kg). Our results show that c-fos expression after global ischemia is NMDA receptor mediated, and mainly found in hippocampal neurons resistant to ischemic injury.