ISSN:
1432-0568
Keywords:
Freeze-fracture
;
Tight junctions
;
Developing nephron
;
Rabbit kidney
;
Junction differentiation
;
Nephrogenesis
Source:
Springer Online Journal Archives 1860-2000
Topics:
Medicine
Notes:
Summary The differentiation and distribution of intercellular junctions especially during the early developmental stages of the rabbit nephron was studied by freeze-fracture electron microscopy. Metanephrogenic cells were found to be connected by sporadic focal tight junctions. During the formation of the renal vesicle similar tight junctions occurred on the periphery as well as near the developing lumen. These focal tight junctions increased in size and coalesced to broad zonulae occludentes lining the vesicular lumen at a later stage. Broad occluding junctions were also observed in the different nephron segments of the S-shaped stage. Ultrastructurally, these early maculae and zonulae occludentes consisted of beaded rows of particles. As development progressed, continuous tight junctions formed, whereas the number of strands decreased with the exception of the distal tubule. In contrast to the parietal glomerular epithelium, the initial occluding zonules of the visceral glomerular cells were gradually reduced to maculae occludentes, and finally disappeared. These results suggest that zonulae occludentes appear synchronously with the establishing lumen; the ultrastructural differentiation of tight junction strands seems to be completed with the onset of glomerular filtration.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00315707
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