NEUROLOGIC AND CYTOLOGIC OUTCOME FOLLOWING REPEATED ISCHEMIA - EFFECTOF PENTOBARBITAL

We examined clinical recovery from repeated brain ischemic insults tha t have been reported to affect cytologic outcome. Brain ischemia was i nduced in the rat by four-vessel occlusion. A 30-min ischemia was give n as a single insult or induced in animals made ischemic 24 h earlier by a 10-min insult but exempt both of brain hypoperfusion and neurolog ic deficit in spite of a partial necrosis of the CA1 sector: of hippoc ampus. Repeated ischemia was associated with a significantly poorer cl inical outcome as indicated by an increase in percentage of rats that exhibited postischemic seizure activity combined with the percentage o f unconvulsive rats exhibiting neurologic deficits after 72 h of reper fusion (81% vs. 50% after a single 30-min ischemia). Examination of hi ppocampal damage showed that neurons surviving the first ischemia did not acquire resistance to the second ischemia. Pentobarbital given fro m start of overt seizures (30 to 60 mg/kg, IP, thrice daily) was able to stop convulsions and to antagonize processes involved in ischemia-i nduced neuronal death of CAI hippocampus.