Physiological and biochemical study of temporary cerebral ischemic rats produced by bilateral vertebral and carotid artery occlusion

We investigated the changes of behavioral, electrophysiological and biochemical parameters during and after global cerebral ischemia in rats. Global cerebral ischemia was produced by the temporary occlusion of both common carotid arteries 24 hr after the permanent electrocauterization of bilateral vertebral arteries. Just before recirculation following 10 or 30 min of cerebral ischemia, loss of'righting reflex, flattenning of cortical EEG activity, and detrimental decrease of ATP content and marked increase of lactate content in the cerebrum were observed. The alterations of all parameters completely recovered within 60 min after recirculation in 10-min cerebral ischemic rats. However, the 30-min cerebral ischemic rats showed almost no recovery after recirculation, suggesting that some irreversible damages are produced in the cerebrum of the 30-min ischemic rat. On the other hand, it was found that the auditory brain stem evoked response (ABER) and ATP content in the pons plus medulla were only slightly affected by the ischemic procedure, which indicates that the ischemic damages do not ensue in the lower part of the brain stem.