Organization of tight junctions in the choroid plexus epithelium

1978 ◽  
Vol 36 (2) ◽  
pp. 336-337
Author(s):  
B. Van Deurs ◽  
J. K. Koehler
Keyword(s):  
Choroid Plexus ◽  
Present Report ◽  
Freeze Fracture ◽  
Barrier Properties ◽  
Cell Junctions ◽  
Structural Basis ◽  
Apical Surface ◽  
Choroid Plexus Epithelium ◽  
Solid Nitrogen ◽  
Special Composition

The choroid plexus epithelium constitutes a blood-cerebrospinal fluid (CSF) barrier, and is involved in regulation of the special composition of the CSF. The epithelium is provided with an ouabain-sensitive Na/K-pump located at the apical surface, actively pumping ions into the CSF. The choroid plexus epithelium has been described as “leaky” with a low transepithelial resistance, and a passive transepithelial flux following a paracellular route (intercellular spaces and cell junctions) also takes place. The present report describes the structural basis for these “barrier” properties of the choroid plexus epithelium as revealed by freeze fracture.Choroid plexus from the lateral, third and fourth ventricles of rats were used. The tissue was fixed in glutaraldehyde and stored in 30% glycerol. Freezing was performed either in liquid nitrogen-cooled Freon 22, or directly in a mixture of liquid and solid nitrogen prepared in a special vacuum chamber. The latter method was always used, and considered necessary, when preparations of complementary (double) replicas were made.

scholarly journals Tight junctions in the choroid plexus epithelium. A freeze-fracture study including complementary replicas.

1979 ◽  
Vol 80 (3) ◽  
pp. 662-673 ◽  
Author(s):  
B van Deurs ◽  
J K Koehler
Keyword(s):  
Choroid Plexus ◽  
Tight Junctions ◽  
Freeze Fracture ◽  
Choroid Plexus Epithelium ◽  
Sprague Dawley ◽  
Fixed Tissue ◽  
Average Width ◽  
Mean Values ◽  
Sprague Dawley Rats ◽  
Fracture Study

The tight junctions of the choroid plexus epithelium of rats were studied by freeze-fracture. In glutaraldehyde-fixed material, the junctions exhibited rows of aligned particles and short bars on P-faces, the E-faces showing grooves bearing relatively many particles. A particulate nature of the junctional strands could be established by using unfixed material. The mean values of junctional strands from the lateral, third, and fourth ventricles of Lewis rats were 7.5 +/- 2.6, 7.4 +/- 2.2, and 7.5 +/- 2.4; and of Sprague-Dawley rats 7.7 +/- 3.4, 7.4 +/- 2.3, and 7.3 +/- 1.6. Examination of complementary replicas (of fixed tissue) showed that discomtinuities are present in the junctional strands: 42.2 +/- 4.6% of the length of measured P-face ridges were discontinuities, and the total amount of complementary particles in E-face grooves constituted 17.8 +/- 4.4% of the total length of the grooves, thus approximately 25% of the junctional strands can be considered to be discontinuous. The average width of the discontinuities, when corrected for complementary particles in E-face grooves, was 7.7 +/- 4.5 nm. In control experiments with a "tighter" tight junction (small intestine), complementary replicas revealed that the junctional fibrils are rather continuous and that the very few particles in E-face grooves mostly filled out discontinuities in the P-face ridges. Approximately 5% of the strands were found to be discontinuous. These data support the notion that the presence of pores in the junctional strands of the choroid plexus epithelium may explain the high transepithelial conductance in a "leaky" epithelium having a high number of junctional strands. However, loss of junctional material during fracturing is also considered as an alternative explanation of the present results.

scholarly journals T-Lymphocytes Traffic into the Brain across the Blood-CSF Barrier: Evidence Using a Reconstituted Choroid Plexus Epithelium

PLoS ONE ◽  
2016 ◽  
Vol 11 (3) ◽  
pp. e0150945 ◽  
Author(s):  
Nathalie Strazielle ◽  
Rita Creidy ◽  
Christophe Malcus ◽  
José Boucraut ◽  
Jean-François Ghersi-Egea
Keyword(s):  
T Lymphocytes ◽  
Choroid Plexus ◽  
Choroid Plexus Epithelium ◽  
The Brain

Immunoreactivities for hepcidin, ferroportin, and hephaestin in astrocytes and choroid plexus epithelium of human brains

2019 ◽  
Vol 40 (1) ◽  
pp. 75-83 ◽  
Author(s):  
Ken Yanase ◽  
Naoya Uemura ◽  
Yoichi Chiba ◽  
Ryuta Murakami ◽  
Ryuji Fujihara ◽  
...  
Keyword(s):  
Choroid Plexus ◽  
Choroid Plexus Epithelium ◽  
Human Brains

Altered pHi regulation and Na+/HCO3− transporter activity in choroid plexus of cilia-defective Tg737orpk mutant mouse

2007 ◽  
Vol 292 (4) ◽  
pp. C1409-C1416 ◽  
Author(s):  
Boglarka Banizs ◽  
Peter Komlosi ◽  
Mark O. Bevensee ◽  
Erik M. Schwiebert ◽  
Phillip D. Bell ◽  
...  
Keyword(s):  
Ion Transport ◽  
Choroid Plexus ◽  
Perinatal Period ◽  
Ependymal Cells ◽  
Intracellular Camp ◽  
Transport Activity ◽  
Wild Type ◽  
Choroid Plexus Epithelium ◽  
Fluid Movement ◽  
Camp Levels

Tg737 orpk mice have defects in cilia assembly and develop hydrocephalus in the perinatal period of life. Hydrocephalus is progressive and is thought to be initiated by abnormal ion and water transport across the choroid plexus epithelium. The pathology is further aggravated by the slow and disorganized beating of motile cilia on ependymal cells that contribute to decreased cerebrospinal fluid movement through the ventricles. Previously, we demonstrated that the hydrocephalus phenotype is associated with a marked increase in intracellular cAMP levels in choroid plexus epithelium, which is known to have regulatory effects on ion and fluid movement in many secretory epithelia. To evaluate whether the hydrocephalus in Tg737 orpk mutants is associated with defects in ion transport, we compared the steady-state pHi and Na+-dependent transport activities of isolated choroid plexus epithelium tissue from Tg737 orpk mutant and wild-type mice. The data indicate that Tg737 orpk mutant choroid plexus epithelium have lower pHi and higher Na+-dependent HCO3− transport activity compared with wild-type choroid plexus epithelium. In addition, wild-type choroid plexus epithelium could be converted to a mutant phenotype with regard to the activity of Na+-dependent HCO3− transport by addition of dibutyryl-cAMP and mutant choroid plexus epithelium toward the wild-type phenotype by inhibiting PKA activity with H-89. Together, these data suggest that cilia have an important role in regulating normal physiology of choroid plexus epithelium and that ciliary dysfunction in Tg737 orpk mutants disrupts a signaling pathway leading to elevated intracellular cAMP levels and aberrant regulation of pHi and ion transport activity.

scholarly journals A thin-section and freeze-fracture study of microfilament-membrane attachments in choroid plexus and intestinal microvilli.

1978 ◽  
Vol 79 (3) ◽  
pp. 774-787 ◽  
Author(s):  
N S McNutt
Keyword(s):  
Choroid Plexus ◽  
Thin Section ◽  
Brush Border ◽  
Freeze Fracture ◽  
Similar Type ◽  
Heavy Meromyosin ◽  
Thin Sections ◽  
Intestinal Brush Border ◽  
Fracture Study ◽  
20 Nm

Choroid plexus and intestinal microvilli in thin sections have microfilaments in the cytoplasm adjacent to the membranes, and in replicas have broken strands of filaments in both cytoplasm and on E faces of plasm membranes. The microfilaments contain actin as indicated by their binding of heavy meromyosin (HMM). In sections of choroid plexus, the microfilaments are 7-8 nm in diameter and form a loose meshwork which lies parallel to the membrane and which is connected to the membranes both by short, connecting filaments (8 times 30 nm) and dense globules (approximately 15-20 nm). The filamentous strands seen in replicas are approximately 8 nm in diameter. Because they are similar in diameter and are connected to the membrane, these filamentous strands seen in replicas apparently represent the connecting structures, portions of the microfilaments, or both. The filamentous strands attached to the membrane are usually associated with the E face and appear to be pulled through the P half-membrane. In replicas of intestinal brush border microvilli, the connecting strands attaching core microfilaments to the membrane are readily visualized. In contrast, regions of attachment of core microfilaments to dense material at the tips of microvilli are associated with few particles on P faces and with few filamentous strands on the E faces of the membranes. Freeze-fracture replicas suggest a morphologically similar type of connecting strand attachment for microfilament-membrane binding in both choroid plexus and intestinal microvilli, despite the lack of a prominent core bundle of microfilaments in choroid plexus microvilli.

Expression of neuropeptide processing enzymes and neurosecretory proteins in ependyma and choroid plexus epithelium

1993 ◽  
Vol 617 (2) ◽  
pp. 238-248 ◽  
Author(s):  
Patricia Gee ◽  
C. Harker Rhodes ◽  
Lloyd D. Fricker ◽  
Ruth Hogue Angeletti
Keyword(s):  
Choroid Plexus ◽  
Choroid Plexus Epithelium ◽  
Processing Enzymes
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