ISSN:
1432-0878
Keywords:
Astrocytes
;
Ependymal cells
;
Circumventricular organs
;
Tight junctions
;
Orthogonal arrays of particles
;
Freeze-fracturing
;
Rat
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
,
Medicine
Notes:
Summary Ependymal cells in the ventricular wall and in several circumventricular organs of the rat were compared by means of freeze-fracturing. In principle, tight junctions and orthogonal arrays of particles (OAP) do not coexist in the cells bordering the ventricular wall: (1) Ordinary ependymal cells of the rat possess OAP and are devoid of tight junctions. (2) Epithelial cells of the rat choroid plexus are connected by tight junctions; OAP are lacking here. In some cases, however, tight junctions and OAP coexist in the same cell. In the boundary zone between choroid plexus and ependyma of the rat, the density of OAP is very low, whereas the tight junctions are well developed. In the subfornical and the subcommissural organ (SCO) of the rat both structures are poorly developed; in the SCO they occur segregated in different membranous areas. An overview of the literature confirms that tight junctions and OAP mostly exclude each other. The possibility that in astrocytes and ependymal cells tight junctions may have been replaced by OAP during phylogeny is briefly discussed.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00216492
