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Ontogenetic development of diffusional restriction to protein at the pial surface of the rat brain: an electron microscopical study


Balslev, Y and Saunders, NR and Mollgard, K, Ontogenetic development of diffusional restriction to protein at the pial surface of the rat brain: an electron microscopical study, Journal of Neurocytology, 26, (3) pp. 133-148. ISSN 0300-4864 (1997) [Refereed Article]

DOI: doi:10.1023/A:1018527928760


Blood-brain, blood-CSF and ventricular CSF-brain barriers to protein, are present very early in brain development. In order to determine whether the outer pial surface of the brain also restricts free penetration of macromolecules, the dorso-lateral part of the sensorimotor cortex from rats at embryonic day 12 (E12), 14, 16, and 18, the day of birth (P0), and adult rat, was studied by electron microscopical techniques. Potassium ferrocyanide, Ruthenium Red and immunogold labelling of endogenous albumin were used to investigate junctional structures and the sites of restriction to albumin diffusion. At E12, large fenestrated sinusoids were present in the pia-arachnoid and the brain surface was formed by an incomplete layer of neuroepithelial and presumptive radial glial end feet, but capillaries in the pia-arachnoid showed no fenestrations at E14 or later. From E14, we observed the progressive appearance of distinct junctional structures between the glial end feet which, to our knowledge, have not been described before. Analysis of albumin distribution from E16 to P0 suggests that the junctions may contribute to restriction of diffusion between the subarachnoid space and the brain extracellular fluid. The restriction to the penetration of protein at both the pial and the ependymal surfaces may ensure the isolation of the neural environment during a critical phase in development of the nervous system. The changes in the structure of the junctions between E12 and P0 suggests a transitional series of embryonic junctional types, which eventually give way to the mature junctions of the adult. Parallels between the embryonic glial junctions and junctions described in adult invertebrate brain, suggest some interesting parallels in junctional development in phylogeny and ontogeny.

Item Details

Item Type:Refereed Article
Research Division:Biomedical and Clinical Sciences
Research Group:Neurosciences
Research Field:Central nervous system
Objective Division:Expanding Knowledge
Objective Group:Expanding knowledge
Objective Field:Expanding knowledge in the environmental sciences
UTAS Author:Saunders, NR (Professor Norman Saunders)
ID Code:10830
Year Published:1997
Web of Science® Times Cited:26
Deposited By:Anatomy and Physiology
Deposited On:1997-08-01
Last Modified:2011-08-11

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