Active transport of chloride by lateral ventricle choroid plexus of the rat

1985 ◽  
Vol 249 (4) ◽  
pp. F470-F477 ◽  
Author(s):  
Q. R. Smith ◽  
C. E. Johanson

The nature of Cl transport and its relation to Na and K transport were analyzed in adult rat lateral ventricle choroid plexus incubated in cerebrospinal fluid (CSF) medium at 37 degrees C and PCO2 = 30 mmHg. In synthetic CSF (extracellular Cl [( Cl]o) = 130 mM), the intracellular Cl [( Cl]i) was three times that estimated for passive distribution. Choroid plexus [Cl]i was not determined by Donnan distribution because [Cl]i remained constant at approximately 50 mM while the [K]i/[K]o ratio was varied 10-fold by drugs and cation substitutions. A [Cl]i/[Cl]o ratio of approximately 0.38 was found when [Cl]o was varied from 15 to 130 mM by isosmotic replacement of Cl with methyl sulfate or isethionate. However, the [Cl]i/[Cl]o ratio increased to greater than 1.0 when [Cl]o was lowered below 5 mM. Reduction in bath temperature to 15 degrees C (CSF PCO2 = 50 mmHg) increased both [Cl]i/[Cl]o and [HCO3]i/[HCO3]o to approximately 0.6. SITS, an inhibitor of Cl-HCO3 transport, reduced [Cl]i by 18 mM, decreasing the [Cl]i/[Cl]o ratio close to the equilibrium value. In contrast, neither furosemide (10(-3) M) nor low CSF [Na]o (3 mM) reduced Cl accumulation. It is concluded that uphill movement of Cl into choroid plexus epithelium occurs primarily by Cl-HCO3 antiport and not by Na-Cl symport.

Author(s):  
Lacey M. Carter ◽  
Benjamin Cornwell ◽  
Naina L. Gross

AbstractChoroid plexus cysts consist of abnormal folds of the choroid plexus that typically resolve prior to birth. Rarely, these cysts persist and may cause outflow obstruction of cerebrospinal fluid. We present a 5-month-old male born term who presented with lethargy, vomiting, and a bulging anterior fontanelle. Magnetic resonance imaging showed one large choroid plexus cyst had migrated from the right lateral ventricle through the third ventricle and cerebral aqueduct into the fourth ventricle causing outflow obstruction. The cyst was attached to the lateral ventricle choroid plexus by a pedicle. The cyst was endoscopically retrieved from the fourth ventricle intact and then fenestrated and coagulated along with several other smaller cysts. Histologic examination confirmed the mass was a choroid plexus cyst. The patient did well after surgery and did not require any cerebrospinal fluid diversion. Nine months after surgery, the patient continued to thrive with no neurological deficits. This case is the first we have found in the literature of a lateral ventricular choroid plexus cyst migrating into the fourth ventricle and the youngest of any migrating choroid plexus cyst. Only three other cases of a migrating choroid plexus cyst have been documented and those only migrated into the third ventricle. New imaging advances are making these cysts easier to identify, but may still be missed on routine sequences. High clinical suspicion for these cysts is necessary for correct treatment of this possible cause of hydrocephalus.


2017 ◽  
Vol 23 (8) ◽  
pp. 997-1003 ◽  
Author(s):  
Jason K Karimy ◽  
Jinwei Zhang ◽  
David B Kurland ◽  
Brianna Carusillo Theriault ◽  
Daniel Duran ◽  
...  

2013 ◽  
Vol 450 (1) ◽  
pp. 179-187 ◽  
Author(s):  
Hidekazu Fukuda ◽  
Taku Hirata ◽  
Nobuhiro Nakamura ◽  
Akira Kato ◽  
Katsumasa Kawahara ◽  
...  

Secretion of HCO3− at the apical side of the epithelial cells of the choroid plexus is an essential step in the formation of cerebrospinal fluid. Anion conductance with a high degree of HCO3− permeability has been observed and suggested to be the major pathway for HCO3− transport across the apical membrane. Recently, it was found that NBC (Na+/HCO3− co-transporter) 4, an electrogenic member of the NBC family, was expressed in the choroid plexus. We found that a novel variant of the NBC4 [NBC4g/Slc4a5 (solute carrier family 4, sodium bicarbonate co-transporter, member 5)] is almost exclusively expressed in the apical membrane of rat choroid plexus epithelium at exceptionally high levels. RNA interference-mediated knockdown allowed the functional demonstration that NBC4g is the major player in the HCO3− transport across the apical membrane of the choroid plexus epithelium. When combined with a recent observation that in choroid plexus epithelial cells electrogenic NBC operates with a stoichiometry of 3:1, the results of the present study suggest that NBC4g mediates the efflux of HCO3− and contributes to cerebrospinal fluid production.


1985 ◽  
Vol 249 (4) ◽  
pp. F478-F484 ◽  
Author(s):  
C. E. Johanson ◽  
Z. Parandoosh ◽  
Q. R. Smith

[14C]DMO distribution was used to measure steady-state intracellular pH (pHi) and [HCO3]i in adult rat choroid plexus (CP) incubated in synthetic cerebrospinal fluid (CSF) for 30 min. In controls at 37 degrees C, mean pHi (6.95 at PCO2 = 30 mmHg) was close to corresponding in vivo values; and [HCO3]i/[HCO3]csf, i.e., rHCO3, was 0.37. At normal [HCO3]csf = 18 mM, cell HCO3 was accumulated threefold above electrochemical equilibrium (as estimated from Em = -50 mV). [HCO3]i decreased proportionally with [HCO3]csf, as the latter was altered from 47 to 9 mM; in severe extracellular acidosis [( HCO3]csf = 3.7 mM), [HCO3]i was not reduced further and so rHCO3 rose to 0.66. Except in low [HCO3]csf, acetazolamide and ouabain (10(-4) M) caused small depletion of cell HCO3. 4-Acetamido-4'-isothiocyanatostilbene-2,2'-disulfonic acid lowered [HCO3]i by 60%, thus decreasing rHCO3 (0.16) and rCl (0.25) to values close to estimated equilibrium distribution (0.15). Substitution of CSF Cl with isethionate resulted in marked alkalinization of pHi when [Cl]csf was depleted to 12 mM. Augmented PCO2 associated with temperature reduction to 15 degrees C elevated [HCO3]i, thereby increasing rHCO3 (to 0.66) as well as rCl. Anion distribution ratios indicate heteroanion exchange in mammalian CP.


Physiology ◽  
2010 ◽  
Vol 25 (4) ◽  
pp. 239-249 ◽  
Author(s):  
Helle H. Damkier ◽  
Peter D. Brown ◽  
Jeppe Praetorius

A stable intraventricular milieu is crucial for maintaining normal neuronal function. The choroid plexus epithelium produces the cerebrospinal fluid and in doing so influences the chemical composition of the interstitial fluid of the brain. Here, we review the molecular pathways involved in transport of the electrolytes Na+, K+, Cl−, and HCO3− across the choroid plexus epithelium.


2016 ◽  
Vol 146 (3) ◽  
pp. 325-336 ◽  
Author(s):  
Alberto E. Ayala-Sarmiento ◽  
Enrique Estudillo ◽  
Gilberto Pérez-Sánchez ◽  
Arturo Sierra-Sánchez ◽  
Lorenza González-Mariscal ◽  
...  

1982 ◽  
Vol 60 (3) ◽  
pp. 405-409 ◽  
Author(s):  
James M. Melby ◽  
Lewis C. Miner ◽  
Donal J. Reed

The effect of acetazolamide and furosemide on choroid plexus (CP) production and electrolyte composition of cerebrospinal fluid (CSF) from the cat CP in situ was investigated. Both drugs decreased CSF production by the CP by 50–90% from a control rate of 0.53 μL ∙ min−1 ∙ mg−1 CP within 1.5–2.5 h after the start of drug treatment. The results were similar whether the drug was administered intravenously or applied directly to the CSF side of the CP. A number of experiments in which the effect of administering drugs via the chamber were studied were continued with the drugs removed by washing the preparation with drug-free artificial CSF and the responses measured. The results demonstrated that the effects of acetazolamide and furosemide were reversed during the 1st h following the washout. Both drugs decreased K concentration of nascent CSF when administered intravenously and furosemide also did so when administered on the CSF side of the CP. It is concluded from these and previous data that acetazolamide and furosemide markedly inhibit the transport mechanism(s) in the cat CP that are responsible for CP secretion which represents about 40–60% of the total CSF production and that K transport is also affected.


2004 ◽  
Vol 286 (3) ◽  
pp. C601-C610 ◽  
Author(s):  
J. Praetorius ◽  
L. N. Nejsum ◽  
S. Nielsen

The choroid plexus epithelium of the brain ventricular system produces the majority of the cerebrospinal fluid and thereby defines the ionic composition of the interstitial fluid in the brain. The transepithelial movement of Na+ and water in the choroid plexus depend on a yet-unidentified basolateral stilbene-sensitive [Formula: see text]-[Formula: see text] uptake protein. Reverse transcriptase-polymerase chain reaction (RT-PCR) analysis revealed the expression in the choroid plexus of SLC4A10 mRNA, which encodes a stilbene-sensitive [Formula: see text]-[Formula: see text] transporter. Anti-COOH-terminal antibodies were developed to determine the specific expression and localization of this [Formula: see text]-[Formula: see text] transport protein. Immunoblotting demonstrated antibody binding to a 180-kDa protein band from mouse and rat brain preparations enriched with choroid plexus. The immunoreactive band migrated as a 140-kDa protein after N-deglycosylation, consistent with the predicted molecular size of the SLC4A10 gene product. Bright-field immunohistochemistry and immunoelectron microscopy demonstrated strong labeling confined to the basolateral plasma membrane domain of the choroid plexus epithelium. Furthermore, the stilbene-insensitive [Formula: see text]-[Formula: see text] cotransporter, NBCn1, was also localized to the basolateral plasma membrane domain of the choroid plexus epithelium. Hence, we propose that the SLC4A10 gene product and NBCn1 both function as basolateral [Formula: see text] entry pathways and that the SLC4A10 gene product may be responsible for the stilbene-sensitive [Formula: see text]-[Formula: see text] uptake that is essential for cerebrospinal fluid production.


2017 ◽  
Vol 312 (6) ◽  
pp. C673-C686 ◽  
Author(s):  
Jeppe Praetorius ◽  
Helle Hasager Damkier

The choroid plexus epithelium is a secretory epithelium par excellence. However, this is perhaps not the most prominent reason for the massive interest in this modest-sized tissue residing inside the brain ventricles. Most likely, the dominant reason for extensive studies of the choroid plexus is the identification of this epithelium as the source of the majority of intraventricular cerebrospinal fluid. This finding has direct relevance for studies of diseases and conditions with deranged central fluid volume or ionic balance. While the concept is supported by the vast majority of the literature, the implication of the choroid plexus in secretion of the cerebrospinal fluid was recently challenged once again. Three newer and promising areas of current choroid plexus-related investigations are as follows: 1) the choroid plexus epithelium as the source of mediators necessary for central nervous system development, 2) the choroid plexus as a route for microorganisms and immune cells into the central nervous system, and 3) the choroid plexus as a potential route for drug delivery into the central nervous system, bypassing the blood-brain barrier. Thus, the purpose of this review is to highlight current active areas of research in the choroid plexus physiology and a few matters of continuous controversy.


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