Limited but evident protective effects of MK-801 and pentobarbital on neuronal damage following forebrain ischemia in the gerbil under normothermic conditions.

The purpose of this study was to examine the protective effects of an N-methyl-D-aspartate receptor antagonist, MK-801, and pentobarbital against neuronal damage in a global ischemia model under controlled body temperature. Gerbils were subjected to 3 and 5 min of bilateral common carotid artery occlusion. MK-801 (1 and 5 mg/kg, i.p.), administered 30 min before ischemia, significantly attenuated the degeneration of hippocampal CA1 pyramidal cells after 3 min of ischemia in a dose dependent manner, but had no such effects after 5 min of ischemia. Pentobarbital (40 mg/kg, i.p.) also protected against CA1 damage after 3 min of ischemia but not after 5 min of ischemia. Thus, we confirmed the protective effects of these agents under normothermic conditions, although these effects were limited to shorter periods of ischemia.