Post-traumatic migration and emergence of a novel cell line upon the ependymal surface of the third cerebral ventricle in the adult mammalian brain

This investigation describes the migration and emergence of significant num bers of what appear to be neuron-like cells upon the surface of the median eminence of the adult rodent neurohypophyseal system of the endocrine hypot halamus following the trauma of hypophysectomy. These cells appear to migra te through the neuropil of the underlying median eminence and emerge in lar ge numbers upon the surface of the third cerebral ventricle within 7 days f ollowing hypophysectomy (axotomy) of supraoptic (SON) and paraventricular n eurites (PVN) of the adult neurohypophyseal system. Previous investigations have demonstrated regeneration of the neural stem and neural lobe in a var iety of mammalian species (Adams et al., J Comp Neurol, 1969;135:121-144; B eck et al., Neuroendocrinology, 1969;5:161-182; Scott et al., Exp Neurol, 1 995;131-1:23-39; Scott and Hansen, Vir Med 1997;124:249-261). It also has b een demonstrated that the process of regeneration is invariably accompanied by the upregulation of nitric oxide synthase (MOS), the enzyme that cataly zes arginine to nitric oxide (NO) and that both neurohypophyseal regenerati on, as well as migration and emergence of neuron-like cells upon the surfac e of the adjacent third cerebral ventricle, is associated with the up-regul ation of NOS and increased expression of NO. It also has been amply demonst rated that this entire process of neurohypophyseal regeneration and cell mi gration is completely inhibited by the introduction of the antagonist of ni tric oxide, namely, nitroarginine (Scott let al., Exp Neurol, 1995;131-1:23 -39; Scott and Hansen, Vir Med, 1997;124:249-261). The emergence and migrat ory dynamics of this novel cell line upon the floor of the rodent third cer ebral ventricle are discussed with respect to the role of the ubiquitous fr ee radical NO and the implications and potential clinical applications of n euronal migration following trauma in the human central nervous system (CNS ). Anat Rec 256:233-241, 1999. (C) 1999 Wiley-Liss, Inc.