Cells Proliferating in Vitro to Local Brain Injury Are Primarily of Hematic Origin and Differ from Those Associated with Anterograde Degeneration

Abstract
(a) The PR elicited by excitotoxic destruction of intrinsic neurons in the CN has a rapid onset, peaks within 2 weeks, and persists indefinitely; (b) the majority of the proliferating cells are not intrinsic to the CNS but are of hematic origin; (c) a small mirror-image response is seen in the contralateral CN; (d) the proliferating response in anterogradely degenerating terminals in SN differs in time course, magnitude, and phenotypically from that initiated by direct neuronal loss. We conclude that the majority of proliferating cells at the site of selective neuronal injury in brain are of hematic origin in contrast to that initiated during anterograde degeneration, which consists primarily of intrinsic cells of brain (glia).