Hypothermic prevention of the hippocampal damage following ischemia in Mongolian gerbils comparison between intraischemic and brief postischemic hypothermia.

The protective effect on ischemic hippocampal damage was compared between intra- and postischemic hypothermia in Mongolian gerbils and its regional preference was evaluated. Male Mongolian gerbils were subjected to transient forebrain ischemia and the hippocampus 7 days after ischemia was examined histologically. In the intraischemic hypothermia (29-31 degrees C) group, CA1 damage was completely prevented in spite of spontaneous postischemic hyperthermia. In contrast, the same degree of brief postischemic hypothermia exerted no preventive effect. While neurons in the subiculum and CA2 sector were also protected against ischemic damage by intraischemic hypothermia, injured pyramidal neurons were always seen in the CA4 sector.