CONTINUOUS MONITORING AND REGULATING OF BRAIN TEMPERATURE IN THE CONSCIOUS AND FREELY MOVING ISCHEMIC GERBIL - EFFECT OF MK-801 ON DELAYED NEURONAL DEATH IN HIPPOCAMPAL CA1

Many glutamate antagonists have been reported to have a neuroprotectiv e effect against ischemic brain damage; however, some of them have bee n also reported to induce hypothermia that confers remarkable neuropro tection against the damage, In order to avoid the confounding effects of hypothermia, we assembled a telemeter-based brain temperature contr ol system that allows continuous monitoring and regulating of brain te mperature during an ischemic insult and in the post-ischemic period in conscious and freely moving animals, Experiments were performed in ge rbils that were subjected to administration of MK-801 (3, 5, and 10 mg /kg) and/or to 5-min ischemia, The system monitored continuous changes in brain temperature and regulated brain temperature at normothermic levels, revealing that a neuroprotective effect of 3 mg/kg MK-801 agai nst ischemia-induced delayed hippocampal CA1 neuronal death was mainly due to hypothermia, whereas a high dose of MK-801 (5 and 10 mg/kg) pr oduced a neuroprotective effect even when the brain temperature was ma intained at normothermic levels, These results indicate that this syst em is very useful to test potential antiischemic agents, especially wh en the agents have hypothermic side effects. (C) 1997 Wiley-Liss, Inc.