[Protective effect of mannitol in cerebral infarction--CT findings and physiological observation in experimental cerebral infarction in dogs].
Sequential changes of low density area in CT scan and sequential changes of neurons in light microscopical study following occlusion were investigated. Similar observations were also made with the administration of 20% mannitol (2g/kg) prior to occlusion to determine the effect in preventing cerebral infarction. In these experiments we used our previously published "complete cerebral hemispheric infarction model in dogs" which was produced by ipsilateral occlusion of the A1 and A2 segment of anterior cerebral artery, ophthalmic artery, internal carotid artery, middle cerebral artery and the junction of the posterior communicating artery and posterior cerebral artery. Sequential changes in CT findings of 4 untreated control animals showed a low density area 3 hours after the occlusion in each animals. After 6 hours, these areas became more distinct. On the other hand in 3 mannitol treated animals, the low density area was not distinct 6 hours after the occlusion. In light microscopical study of 5 untreated control animals, no normal neurons were seen 4 hours after occlusion, and shrinkage and swelling was seen in roughly 80% of the neurons 6 hours after the occlusion. However, in 2 mannitol treated animals, 30% normal neurons were seen 4 hours after occlusion, and shrinkage and swelling was seen only 10-20% 6 hours after the occlusion.