Abstract
To demonstrate the presence, or absence, and the nature of the vulnerability differences in hippocampal neurons at early stages of ischemia without recirculation, immunohistochemical study with antiserum to tubulin was performed on the brains of Mongolian gerbils obtained 5 min to 3 hours after unilateral occlusion of the posterior communicating artery. It has been demonstrated by the previous studies that the occlusion of this vessel causes severe and constant ischemia in the hippocampus, and that disappearence in immunoreactivity of tubulin can be a sensitive indicator for neuronal involvement in cerebral ischemia. During the 3-hour period of ischemia alterations in immunoreactivity of tubulin were more readily produced in the pyramidal cells of the sector CA1 than in those of other sectors; in dendrites of strata oriens et radiatum than in those of alveus and strata lacunosum et moleculare; in neurons of the pyramidal layer than in those of strata oriens et radiatum. Additionally, segmental preservation of tubulin immunoractivity along the small vessels was noted in sectors CA1-2 at 3 hours of ischemia.
The present study demonstrated various kinds of selective vulnerability in hippocampal neurons in the acute stage of ischemia. It was supposed that the observed differences in vulnerability may be associated with a number of unconfirmed factors such as regional differences in neuronal characteristics, differences between neuronal types, or inhomogeneity of partially restored tissue blood flow.
