Brainstem ischemic damage following occlusion of the blood vessels in the rat's posterior cerebral circulation.

Progression of ischemic damage was investigated immunohistochemically in neural dendrites using microtubule-associated protein 2 (MAP2) as a dendritic marker in the rat's brainstem. Neuronal soma and dendrites were clearly stained by this protein but some structures such as axonal bundles, glia and endothelial cells were not visualized. When the anterior inferior cerebellar artery (AICA) was occluded unilaterally for 30 min, a wide ischemic lesion was detected in the occluded side of the brainstem and was observed as a loss of reaction to MAP2. After ischemia for 2 h, loss of reaction in the perikarya and dendrites was seen to expand to the ipsilateral (occluded side) cochlear nucleus. When the basilar artery was blocked, ischemic damage in the vestibular nucleus was more intense than that in the cochlear nucleus. In all specimens studied, differences in anatomical blood supply demonstrated selective tissue vulnerability for ischemic damage.