Choroidal endothelial junctions in primates.
Junctional ultrastructure of endothelial cells of the choroid was studied with freeze-fracture electron microscopy. A network of multi-stranded linear aggregates was found on arterial endothelial membrane E faces in association with the apposing arterial membrane P face strands. The complexity of the junctional strands decreased as vessel diameter decreased. The choriocapillaris showed staggered junctional strands exclusively on the membrane P face. Junctions of venules and veins were represented by plasmalemmal folds with sparse intramembrane particles on the P face. Freeze-fracture cytochemistry with the membrane probe, filipin, revealed two dissimilar membrane domains: one, an area of membrane fluidity at the junctional strands; and the other, identified by the incorporation of cholesterol into the membrane lipid bilayer, a stable membrane domain. The latter was present throughout endothelial membranes, but was especially prominent on the rims of fenestrations of the choriocapillaris.
Nagy
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Department of Ophthalmology, University of Southern California School of Medicine, Los Angeles 90033.
Ogden
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D000818:Animals; D001160:Arterioles / Q000648:ultrastructure; D002196:Capillaries / Q000648:ultrastructure; D002829:Choroid / Q000098:blood supply* / Q000648:ultrastructure; D004730:Endothelium, Vascular / Q000648:ultrastructure*; D005372:Filipin; D005614:Freeze Fracturing; D006651:Histocytochemistry; D007365:Intercellular Junctions / Q000648:ultrastructure*; D008252:Macaca fascicularis; D008253:Macaca mulatta; D014699:Venules / Q000648:ultrastructure
D005372:Filipin