1) 2007
Pflugers Arch. 2007 Apr;454(1):1-18. Epub 2006 Nov 21.
Water and solute secretion by the choroid plexus.
Source
The Water and Salt Research Center & Institute of Anatomy, University of Aarhus, Wilhelm Meyers Allé, 8000 Aarhus, Denmark. jp@ana.au.dkAbstract
The cerebrospinal fluid
(CSF) provides mechanical and chemical protection of the brain and
spinal cord. This review focusses on the contribution of the choroid
plexus epithelium to the water and salt homeostasis of the CSF, i.e. the
secretory processes involved in CSF formation. The choroid plexus
epithelium is situated in the ventricular system and is believed to be
the major site of CSF production. Numerous studies have identified
transport processes involved in this secretion, and recently, the
underlying molecular background for some of the mechanisms have emerged.
The nascent CSF consists mainly of NaCl and NaHCO(3), and the
production rate is strictly coupled to the rate of Na(+) secretion. In
contrast to other secreting epithelia, Na(+) is actively pumped across
the luminal surface by the Na(+),K(+)-ATPase with possible contributions
by other Na(+) transporters, e.g. the luminal Na(+),K(+),2Cl(-)
cotransporter. The Cl(-) and HCO(3) (-) ions are likely transported by a
luminal cAMP activated inward rectified anion conductance, although the
responsible proteins have not been identified. Whereas Cl(-) most
likely enters the cells through anion exchange, the functional as well
as the molecular basis for the basolateral Na(+) entry are not yet
well-defined. Water molecules follow across the epithelium mainly
through the water channel, AQP1, driven by the created ionic gradient.
In this article, the implications of the recent findings for the current
model of CSF secretion are discussed. Finally, the clinical
implications and the prospects of future advances in understanding CSF
production are briefly outlined.
(2) 2001
(2) 2001
Microsc Res Tech. 2001 Jan 1;52(1):49-59.
Mechanisms of CSF secretion by the choroid plexus.
Source
School of Biological Sciences, University of Manchester, Manchester M13 9PT, United Kingdom.Abstract
The epithelial cells of the choroid plexus secrete cerebrospinal fluid
(CSF), by a process that involves the movement of Na(+), Cl(-) and
HCO(3)(-) from the blood to the ventricles of the brain. This creates
the osmotic gradient, which drives the secretion of H(2)O. The
unidirectional movement of the ions is achieved due to the polarity of
the epithelium, i.e., the ion transport proteins in the blood-facing
(basolateral) are different to those in the ventricular (apical)
membranes. Saito and Wright (1983) proposed a model for secretion by the
amphibian choroid plexus, in which secretion was dependent on activity
of HCO(3)(-) channels in the apical membrane. The patch clamp method has
now been used to study the ion channels expressed in rat choroid
plexus. Two potassium channels have been observed that have a role in
maintaining the membrane potential of the epithelial cell, and in
regulating the transport of K(+) across the epithelium. An
inward-rectifying anion channel has also been identified, which is
closely related to ClC-2 channels, and has a significant HCO(3)(-)
permeability. This channel is expressed in the apical membrane of the
epithelium where it may play an important role in CSF secretion. A model
of CSF secretion by the mammalian choroid plexus is proposed that
accommodates these channels and other data on the expression of
transport proteins in the choroid plexus.
Copyright 2001 Wiley-Liss, Inc.
(2) 2009 Kloridin jakautumahäiriö aivoautonomian alueella.
Copyright 2001 Wiley-Liss, Inc.
(2) 2009 Kloridin jakautumahäiriö aivoautonomian alueella.
J Neurol Sci. 2009 Oct 15;285(1-2):146-8. doi: 10.1016/j.jns.2009.06.026. Epub 2009 Jul 12.
Decreased chloride levels of cerebrospinal fluid in patients with amyotrophic lateral sclerosis.
Watanabe S, Kimura T, Suenaga K, Wada S, Tsuda K, Kasama S, Takaoka T, Kajiyama K, Takeda M, Yoshikawa H.
Source
Department of Internal Medicine, Division of Neurology, Hyogo College of Medicine, 1-1, Mukogawa-cho, Nishinomiya, Hyogo 663-8501, Japan. watasho@hyo-med.ac.jpAbstract
Recent
studies have suggested that the elevation of intracellular chloride
contributes to excitotoxic cell death in motor neuron and can be related
to the pathogenesis of amyotrophic lateral sclerosis (ALS). We
investigated whether chloride levels in cerebrospinal fluid
(CSF) and serum were lower in ALS patients than in control patients
with other neurological diseases (OND). We also examined the
relationship between chloride levels and clinical ALS phenotypes. We
measured chloride levels (CSF and serum) in 27 ALS patients and 33 age-
and gender-matched OND controls admitted to our hospital for diagnosis.
The CSF chloride levels were lower in ALS patients (117 [range 102-130]
mmol/L) than in OND controls (126 [range 114-134] mmol/L) . There was no significant difference in CSF chloride
levels among the sub-groups of ALS patients classified according to
their age, gender, duration of illness, clinical state and type of onset
(P>0.05). CSF chloride levels already significantly decreased in ALS
patients at the time of diagnosis. We conclude that the elevation of
intracellular chloride would cause the reduction of chloride in CSF and
be related to the pathogenesis of ALS.
Koko veri 250 mg 100 millissä
Plasma tai seerum 365 mg 100 millissä.
Solut 190 mg 100 millissä
Aivoselkäydinneste 440 mg 100 millissä
Lihaskudos 40 mg 100 millissä
Hermokudos 171 mg 100 millissä.
Kloridin tarvpeen määritelyssä varman tuo likvorin pitoisuus on merkitsevä seikka. Tosin siinä on indiffusible - momentti, aivo retentoi kloridia tuohon aivotyynyosaan, likvoriin.
likvori taas vaihtuu aika nopeasti useita kertoja päivässä. Miten siinä resoptiovaiheessa koridi toimii? Ei ainakaan pyri suuremmalti erittymään poispäin.
- (4) 1969 Aivoselkäydinnesteen kloridipitoisuus on korkeampi kuin muissa kehon nesteissä
Koko veri 250 mg 100 millissä
Plasma tai seerum 365 mg 100 millissä.
Solut 190 mg 100 millissä
Aivoselkäydinneste 440 mg 100 millissä
Lihaskudos 40 mg 100 millissä
Hermokudos 171 mg 100 millissä.
Kloridin tarvpeen määritelyssä varman tuo likvorin pitoisuus on merkitsevä seikka. Tosin siinä on indiffusible - momentti, aivo retentoi kloridia tuohon aivotyynyosaan, likvoriin.
likvori taas vaihtuu aika nopeasti useita kertoja päivässä. Miten siinä resoptiovaiheessa koridi toimii? Ei ainakaan pyri suuremmalti erittymään poispäin.
