ORNITHINE DECARBOXYLASE ACTIVITY AND EDEMA FORMATION IN CEREBRAL-ISCHEMIA OF CONSCIOUS GERBILS

General anesthetic agents often affect the biochemical and physiologic changes triggered by cerebral ischemia. This study examined the regio nal activities of ornithine decarboxylase (ODC) in gerbils subjected t o 5 min of bilateral carotid occlusion without anesthesia. At 2, 4, an d 6 h of reperfusion, significant ODC activity was observed in both th e colter and the hippocampus. Pretreatment with cr-difluoromethylornit hine (DFMO) significantly blocked the ODC activity at 2, 4, and 6 h. S ignificant edema formation was found at 2, 4, and 6 h. At 2 h, edema f ormation was unaffected by administration of DFMO. However, DFMO treat ment reduced later edema formation at 4 and 6 h. These results demonst rate that ODC activity and edema formation are delayed in gerbils afte r the induction of transient ischemia even with the removal of anesthe tic agents and their potentially protective effects. These findings su ggest that ODC activity and ifs induction of delayed cerebral edema ar e specific to cerebral ischemia and not to an anesthetic effect. DFMO treatment reduced both the ODC activity and edema formation, indicatin g a role for polyamines in postischemic edema formation.