[Somatosensory evoked potential and local cerebral glucose utilization in the transient MCA-occluded rat]

Wistar rats were used through the experiments. Preparatory operations for the autoradiography and somatosensory evoked potential (SEP) were performed under 1.5% halothane anesthesia. After a control measurement of SEP, the left MCA was occluded with a micro clip. The animals were divided into 2 groups. In the 1st group (n = 8), the clip was removed 1 hour after MCA occlusion and 4 rats were used for the measurement of local cerebral glucose utilization (LCGU) by 14C-DG autoradiography. Another 4 rats were allowed to recover from anesthesia and used for the histopathological examination after 72 hours. In the 2nd group (n = 8), the clip was removed 2 hours after occlusion and the same procedures were performed. SEP was monitored throughout the experiment. Two positive and one negative peaks were recorded before MCA occlusion. SEP diminished immediately after MCA occlusion. Following the removal of the clip, complete recovery of SEP was observed in the 1st group of rats. However, in the 2nd group, recovery of SEP was minimal. In the 1st group, LCGU in the sensorimotor cortex at 30 minutes after reperfusion showed 22% reduction compared to that of the contralateral homologous area. In the 2nd group, in the contrast, 66% reduction of LCGU was observed. Experimental results indicate that SEP and LCGU in the early recovery period of ischemia are able to predict the reversibility of ischemic brain.