Premium
Plasticity of astrocytes of the ventral glial limitans subjacent to the supraoptic nucleus
Author(s) -
Bobak J.B.,
Salm A.K.
Publication year - 1996
Publication title -
journal of comparative neurology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.855
H-Index - 209
eISSN - 1096-9861
pISSN - 0021-9967
DOI - 10.1002/(sici)1096-9861(19961209)376:2<188::aid-cne2>3.0.co;2-#
Subject(s) - supraoptic nucleus , biology , astrocyte , nucleus , stimulation , anatomy , central nervous system , electron microscope , neuroscience , physics , optics
We present evidence of gross morphological changes in astrocytes of the ventral glial limitans (VGL) associated with a well‐known model of central nervous system (CNS) plasticity: the hypothalamic supraoptic nucleus (SON). Activity of SON magnocellular neuroendocrine cells (MNCs) was stimulated in experimental rats by substitution of 2% saline for drinking water for 2 or 9 days. Light microscopic measures revealed that a significant decrease in VGL thickness, by 34%, occurred with 9 days of stimulation. Astrocyte nuclei of 9‐day dehydrated animals were also found to be 39% closer to the pial surface when compared with controls. Electron microscopy revealed a reorientation of individual astrocytes from a direction perpendicular (vertical) to the pial surface, to one parallel (horizontal) to this region. Vertically oriented astrocytes were found to be greater in the control group, by 49%, when compared with the 9‐day dehydrated group, where cells were predominantly horizontal in orientation. Vertically oriented cells were further analyzed as to the direction of their vertical projections. Control, 2‐day dehydrated and 9‐day rehydrated animals, had more vertical cells which were oriented toward the pial surface when compared with 9‐day dehydrated animals, where the relatively few vertically oriented astrocytes were significantly more likely to project toward the dendritic zone. In animals allowed to rehydrate for 9 days following a period of dehydration, these changes returned toward control levels. We conclude that astrocytes in vivo are capable of reversible gross morphological changes over a relatively short time. © 1996 Wiley‐Liss, Inc.