Neuroscience Center, Massachusetts General Hospital, Charlestown, Massachusetts 02129
![]() |
ABSTRACT |
---|
![]() ![]() ![]() ![]() ![]() ![]() ![]() |
---|
Secretion of cerebrospinal fluid by the choroid plexus can
be inhibited by its cholinergic innervation. We demonstrated that carbachol inhibits the Na+-K+-ATPase in bovine
choroid tissue slices and investigated the mechanism. Many of the
actions of cholinergic agents are mediated by nitric oxide (NO), which
plays important roles in fluid homeostasis. The inhibition of
Na+-K+-ATPase was blocked by the NO synthase
inhibitor [N-nitro-L-arginine
methyl ester] and was quantitatively mimicked by the NO agonists
sodium nitroprusside (SNP) and diethylenetriamine NO. Inhibition by SNP
correlated with an increase in tissue cGMP and was abolished by
1H-[1,2,4]oxadiazolo[4,3-a]quinoxalin-1-one, an inhibitor of soluble guanylate cyclase. Inhibition was mimicked by
the protein kinase G activator 8-bromo-cGMP and by okadaic acid, an
inhibitor of protein phosphatases 1 and 2A. cGMP-dependent protein
kinase inhibitors Rp-8-pCPT-cGMP (0.5-5 µM) and KT-5823 (2.0 µM) did not block the effects of SNP, but higher concentrations of
the more selective inhibitor (Rp-8-pCPT-cGMP) had a pharmacological inhibitory effect on Na+-K+-ATPase. The data
suggest that cholinergic regulation of the
Na+-K+-ATPase is mediated by NO and involves
activation of guanylate cyclase and elevation of cGMP.
nitric oxide; guanosine 3',5'-cyclic monophosphate
![]() |
INTRODUCTION |
---|
![]() ![]() ![]() ![]() ![]() ![]() ![]() |
---|
THE CHOROID
PLEXUSES are highly vascularized tissues located in the large
cavities of the brain: the lateral, third, and fourth ventricles. They
are the major producers of cerebrospinal fluid (CSF). The choroid
plexus epithelial cells are highly enriched in
Na+-K+-ATPase, located at the cell's apical
surface. It has been demonstrated that the 1-,
1-,
2-, and
3-Na+-K+-ATPase isoforms are
expressed in rat choroid plexus epithelium (5, 19, 29, 36, 42,
46, 47). The Na+-K+-ATPase catalyzes the
transfer of 2 K+ from the extracellular space into the cell
and the extrusion of 3 Na+ while hydrolyzing ATP to ADP and
Pi. In fact, choroid plexus Na+-K+-ATPase catalyzes (in concert with ion
channels and carriers) the bulk secretion of Na+ followed
by Cl
and water (1, 4, 24). The
Na+-K+-ATPase also plays a major role in
controlling the composition of CSF, particularly the concentration of
K+, which is lower in CSF than in plasma (2,
34).
Just as renal Na+-K+-ATPase is regulated by complex hormonal mechanisms to maintain plasma electrolytes during dietary and pathological fluctuations of electrolytes and pH, the choroid plexus Na+-K+- ATPase is also subject to several known forms of hormonal regulation. Functionally important sympathetic innervation of choroid vascular bed and epithelium is known (21), and inhibition based on the activation of protein kinase C (15) and protein kinase A (14) has been documented. However, little attention has been paid to the cholinergic innervation of the choroid plexus (10). It has been reported that cholinergic stimulation is associated with increases in the levels of the second messenger cGMP (39). Other physiological studies have demonstrated that intraventricular injection of cholinomimetic agents, such as carbachol and acetylcholine, inhibits CSF secretion (27).
The actions of acetylcholine in relaxing blood vessels are mediated by the free radical nitric oxide (NO) (17). NO is a key paracrine and autocrine regulator in a number of organs and tissues, including blood vessels, immune cells, smooth muscle, nervous system, and some endothelia. Many of the physiological actions of NO are mediated by activation of soluble guanylate cyclase and elevation of cGMP. There is growing evidence that the Na+-K+-ATPase is regulated by NO (for review, see Ref. 11) and other cGMP-generating agents such as carbon monoxide (32) and atrial natriuretic peptide (38). This regulation may be inhibition or stimulation of the Na+-K+-ATPase, depending on the tissue.
There is evidence that the choroid plexus contains a rich distribution of NO synthase (NOS) as demonstrated by NADPH-diaphorase histochemical localization (44) and immunoreactivity for the neuronal NOS isoform (26). Choroid plexus epithelium also contains cGMP, and its target, cGMP-dependent protein kinase (PKG) (7). Previous studies showed that intraventricular injection of atrial natriuretic peptide (known to activate the membrane guanylate cyclase-cGMP system) caused a significant decrease in CSF production that correlated with an increase in cGMP levels in choroid plexus (41). The former observations raise the possibility that cholinergic stimulation and subsequent formation of NO might be capable of altering membrane ion gradients through direct effects on choroid plexus epithelium. This study investigates the role of carbachol, NO, soluble guanylate cyclase, and cGMP in inhibiting the Na+-K+-ATPase activity in bovine choroid plexus. Bovine choroid plexus tissue slices were treated with carbachol and other agents, and Na+-K+-ATPase activity was measured by the hydrolysis of ATP after permeabilization of the slices.
![]() |
METHODS |
---|
![]() ![]() ![]() ![]() ![]() ![]() ![]() |
---|
Tissue preparation. Bovine brain was obtained from an abattoir, and the choroid plexus was dissected from the fourth ventricle. Tissue slices (0.4 × 0.4 × 1 mm) were prepared on a Brinkmann chopper cooled to 4°C and suspended (25-30 mg/ml wet weight) in microdissection buffer containing (in mM) 137 NaCl, 5 KCl, 0.8 MgSO4, 0.25 CaCl2, 1.0 MgCl2, 10 HEPES, and 2 NaOH to adjust pH to 7.4 at 34°C.
Na+-K+-ATPase
and cGMP measurements.
Drugs used in these experiments were added to tubes that contained 1-ml
aliquots of slice suspension. Tubes were incubated for 15 min at 34°C
and then frozen at 80°C. In studies using inhibitors, the
inhibitors were added 3 min before addition of the drug. Tubes were
thawed and centrifuged (1,700 g for 15 min at 4°C), and
supernatant (containing drug) was removed. The supernatant was heated
for 5 min at 90°C, after which 75 mM sodium acetate was added and the
sample was dried and stored for cGMP assay by RIA (Biomedical
Technologies, Stoughton, MA).
Purification of
Na+-K+-ATPase.
Bovine choroid plexus Na+-K+-ATPase was
partially purified according to the modified method of Jørgensen
(22). Tissue was homogenized in buffer containing (in mM)
30 histidine, 1 EDTA, and 250 sucrose (pH 7.2) (HES). Microsomal
fractions were obtained, and tissue pellets were resuspended in equal
volume of HES buffer and buffer containing (in mM) 60 histidine, 2 EDTA, and 6 ATP (pH 7.5), which stabilizes
Na+-K+-ATPase activity for SDS extraction. Low
concentrations of SDS were added, which allowed for the removal of
contaminating proteins, followed by centrifugation on sucrose gradients
to separate the membrane fraction containing
Na+-K+-ATPase. The enzyme was stored in HES
buffer. Protein concentration was determined (as indicated above) using
bovine serum albumin as a standard.
Na+-K+-ATPase -bands were verified with
polyclonal antibody ETYY, which recognizes all three
Na+-K+-ATPase
-isoforms, while
SpETb1 and SpETb2 polyclonal antibodies were used to verify
1- and
2-isoforms, respectively. The
specific activity was 300 µmol
Pi · h
1 · mg
protein
1.
Phosphorylation.
Phosphorylation experiments to test the efficacy of PKG
inhibitors were performed by a modification of the methods of Fotis et
al. (16). Histone 1A (0.5 µg) was incubated for 15 min
at room temperature in buffer containing (in mM) 30 Tris · HCl
(pH 7.4), 5 MgCl2, 100 NaCl, 10 KCl, 1 EDTA, 1 dithiothreitol, and 1 phenylmethylsulfonyl fluoride. Protein
phosphorylation was initiated at room temperature by the addition of
PKG (200 U) and 25 µM [-32P]ATP (final activity
1,000 cpm/pmol) in the presence or absence of cGMP (50 µM) in a final
volume of 25 µl. The reaction was terminated after 15 min by the
addition of an equal volume of Laemmli sample buffer. The
phosphorylation reaction mixture was analyzed on 10% gels by SDS-PAGE
and transferred to nitrocellulose membrane electrophoretically. Phosphoproteins were visualized by autoradiography.
Statistics. Statistical comparisons were performed by ANOVA followed by Fisher's protected least significant difference and Scheffé's F-test for comparison of significant difference among different means.
Chemicals.
Routine reagents, sodium nitroprusside (SNP), ouabain, saponin,
N-nitro-L-arginine methyl ester
(L-NAME), histone, and carbachol were purchased from Sigma
(St. Louis, MO). Others were obtained as follows:
[
-32P]ATP tetra(triethylammonium) salt from DuPont-New
England Nuclear (Boston, MA); 8-bromo-cGMP sodium salt,
1H-[1,2,4]oxadiazolo[4,3-a]quinoxalin-1-one (ODQ), diethylenetriamine NO (DETA-NO) from Sigma-RBI (Natick, MA);
PKG, Rp-8-pCPT-cGMP, and KT-5823 from Calbiochem (La Jolla, CA).
![]() |
RESULTS |
---|
![]() ![]() ![]() ![]() ![]() ![]() ![]() |
---|
A cholinergic agonist, carbachol, inhibits ouabain-sensitive
Na+-K+-ATPase
activity.
Figure 1 shows that 15 min incubation of
choroid plexus tissue slices with the acetylcholine analog carbachol
(100 µM) (27) resulted in a significant inhibition of
ouabain-sensitive Na+-K+-ATPase activity
compared with that of slices treated with vehicle. Ouabain-insensitive
Mg-ATPase activity was not affected. Carbachol at 10 µM had the same
effect as at 100 µM, indicating that the effect is saturated (data
not shown). Because stimulation of the cholinergic system has been
reported to result in an increase in cGMP (39) and many
cholinergic effects are mediated by NO it was of interest to determine
if the cholinergic and NO systems are linked in choroid plexus.
Exposure of bovine choroid plexus tissue slices to L-NAME
(300 µM), a specific inhibitor of NOS, in the presence of carbachol
largely blocked the carbachol-induced decrease in ouabain-sensitive
Na+-K+-ATPase (Fig. 1). These data demonstrate
that the action of carbachol is upstream from NO and predict that
stimulation of the cholinergic system in choroid plexus results in the
release of NO.
|
Cholinergic inhibition of ouabain-sensitive
Na+-K+-ATPase
activity is mimicked by SNP and DETA-NO.
The presence of NOS and Na+-K+-ATPase in
choroid plexus epithelium and the known effects of cGMP in this tissue
suggest that the activation of the NOS system, with subsequent cGMP
synthesis, might regulate the Na+-K+-ATPase.
For these experiments, the coupled assay method was used (see
METHODS for preparation of tissue). After a 15-min exposure of bovine tissue slices to the NO donors SNP (100 µM)
(18) and DETA-NO (9), there was a marked
reduction of Na+-K+-ATPase activity (Fig.
2). The effects of SNP and DETA-NO were specific to Na+-K+-ATPase, because no
measurable changes were observed in the ouabain-insensitive (Mg-ATPase)
activity. Compared with the activity in control choroid plexus,
Na+-K+-ATPase activity in slices treated with
either SNP (100 µM) or DETA-NO (100 µM) was inhibited 30-35%.
|
|
Action of SNP on
Na+-K+-ATPase
involves soluble guanylate cyclase activation.
Many of the actions of NO involve activation of the guanylate cyclase
system. As such it was important to determine if the physiological
action of SNP on Na+-K+-ATPase activity in
choroid plexus was a result of the release of NO and activation of
soluble guanylate cyclase. Exposure of bovine choroid plexus tissue
slices to an inhibitor selective for soluble guanylate cyclase, ODQ (1 µM) (18), partially blocked the SNP-induced inhibition
of the Na+-K+-ATPase (Fig.
4A). Although a number of
physiological actions of NO are mediated by activation of soluble
guanylate cyclase, recent evidence suggests that NO may affect
Na+-K+-ATPase activity directly by modification
of sulfhydryl groups on the Na+-K+-ATPase
molecule (37). That this was not the case here is
demonstrated in Fig. 4B. Incubation of SDS-extracted bovine
choroid Na+-K+-ATPase with SNP (100 µM) or
ODQ (1 µM) did not alter ouabain-sensitive Na+-K+-ATPase activity. This would suggest that
modulation of the Na+-K+-ATPase by SNP is under
the regulation of a second messenger system and that direct effects
such as nitrosylation of sulfhydryl groups were not responsible for the
observations.
|
Increases in cGMP are correlated with NO inhibition of
Na+-K+-ATPase.
Because SNP inhibition of the Na+-K+-ATPase
involved activation of soluble guanylate cyclase, it was of interest to
determine if changes in Na+-K+-ATPase activity
corresponded with alterations in cGMP levels. cGMP was measured in the
supernatants of the same samples that were subsequently assayed for
Na+-K+-ATPase. As shown in Fig.
5, SNP (100 µM) caused substantial
increases in cGMP levels. ODQ, in addition to blocking the SNP-induced
alteration in Na+-K+-ATPase, also caused a
decrease in cGMP generation in response to the drug (Fig. 5). These
results not only provide evidence for the possible involvement of cGMP
in mediating the SNP-induced inhibition of the
Na+-K+-ATPase activity, but also further
support the involvement of soluble guanylate cyclase (vs. membrane
bound guanylate cyclase) in mediating the SNP response in bovine
choroid plexus.
|
Possible involvement of protein phosphorylation in inhibition of
Na+-K+-ATPase
activity.
The nonhydrolyzable analog of cGMP and potent activator of PKG,
8-bromo-cGMP, mimicked the actions of SNP. Figure
6 shows that 8-bromo-cGMP inhibited
ouabain-sensitive Na+-K+-ATPase activity in
bovine choroid plexus slices. Other evidence of the involvement of
protein phosphorylation in regulating the Na+-K+-ATPase activity was obtained from
observations in which okadaic acid at 400 nM, a concentration known to
inhibit both protein phosphatase type 1 and 2A, mimicked the actions of
SNP in inhibiting the Na+-K+-ATPase activity in
bovine choroid plexus (Fig. 6).
|
|
|
![]() |
DISCUSSION |
---|
![]() ![]() ![]() ![]() ![]() ![]() ![]() |
---|
Our studies in choroid plexus demonstrated that stimulation of the cholinergic system caused a significant decrease in ouabain-sensitive Na+-K+-ATPase activity. Furthermore, the NOS inhibitor L-NAME blocked the cholinergic agonist-induced inhibition of the Na+-K+-ATPase, suggesting that activation of the NOS system and subsequent formation of NO mediate the cholinergic response in choroid plexus. These results are consistent with earlier findings that demonstrated cholinergic involvement in regulating CSF secretion (27). Other independent studies have shown that NO release follows stimulation of cholinergic nerves in a number of tissues (13, 17). The NO agonists SNP and DETA-NO caused significant inhibition of the ouabain-sensitive Na+-K+-ATPase activity in choroid plexus. The ability of NO to cause alterations in ouabain-sensitive Na+-K+-ATPase activity is corroborated by previous reports demonstrating NO's regulation of ouabain-sensitive Na+-K+-ATPase activity in other tissues, including stimulation in rat proximal trachea (8) and inhibition in rat kidney medulla (30).
Nitrovasodilators, including SNP, can activate soluble guanylate cyclase in a number of tissues, presumably through release of NO. The ability of the specific soluble guanylate cyclase inhibitor ODQ to antagonize the actions of SNP on the Na+-K+-ATPase would suggest that a direct consequence of NOS stimulation is activation of soluble guanylate cyclase. The inhibition of Na+-K+-ATPase by SNP was consistently associated with an increase in cGMP, as determined from parallel measurements of cGMP and Na+-K+-ATPase activity in SNP-exposed choroid plexus, and this action was mimicked by 8-bromo-cGMP. Further evidence for the involvement of cGMP as a mediator in the action of SNP on Na+-K+-ATPase activity was obtained with agents capable of elevating choroid plexus cGMP levels through a SNP-independent pathway (Nathanson and Ellis, unpublished data). As with SNP, ouabain-sensitive Na+-K+-ATPase activity was inhibited by carbon monoxide and atrial natriuretic peptide, with concomitant increases in cGMP levels. These observations suggest that cGMP may play a wide role in regulating Na+-K+-ATPase activity in many cell types. Our studies, however, do not preclude the involvement of other second messengers, such as protein kinase A or protein kinase C, in modulating Na+-K+-ATPase activity in secretory epithelia.
Because 8-bromo-cGMP is known to be an activator of PKG, the observation that 8-bromo-cGMP mimics the actions of SNP would suggest that PKG might be involved in the inhibition of Na+-K+-ATPase by NO. For technical reasons, we were unable to demonstrate in vivo regulation of Na+-K+-ATPase by PKG in choroid plexus tissue, however. Choroid plexus tissue slices were exposed to either KT-5823 (2.0 µM), a competitive inhibitor at the binding site for ATP (23), or Rp-8-pCPT-cGMP (5.0 µM), which binds to the cGMP binding site (6). Neither drug blocked SNP's effect on Na+-K+-ATPase activity, although similar concentrations have been effective in protecting Na+-K+-ATPase activity in other systems (30). The problem may be one of using a tissue with a high level of NO-pathway constituents. For example, platelets have an unusually high concentration of PKG, therefore 1 mM Rp-8-pCPT-cGMP was required to inhibit it (6). Consequently, concentrations of the inhibitors that work in renal or other tissue preparations may be insufficient for choroid plexus. We did not attempt to use a higher concentration of KT-5823 because of its cross-reactivity with protein kinase A. A higher concentration of Rp-8-pCPT-cGMP (1 mM) inhibited Na+-K+-ATPase activity in tissue slices by itself, and treatment at the same time with SNP did not cause any further change in activity. Curiously, the same phenomenon was reported by de Oliviera Elias et al. (8), who used only 2.0 µM KT-5823 in studies of the stimulation of rat tracheal Na+-K+-ATPase. Because these inhibitors have an inhibitory effect on Na+-K+-ATPase activity by an unknown mechanism, they are not suitable reagents for assessing the participation of PKG in the NO pathway. Direct inhibition of purified Na+-K+-ATPase in the test tube was seen after preincubation in Rp-8-pCPT-cGMP (50 µM), and this may have contributed to the inhibition seen in slices. Such cross-reactivity is not implausible for two proteins with nucleotide binding sites. It is also possible that the cGMP pathway has effects through two different, interacting mechanisms that we do not understand at present.
Other evidence for the role of protein phosphorylation in regulating Na+-K+-ATPase activity in choroid plexus was obtained from studies using the types 1 and 2A protein phosphatase inhibitor okadaic acid. The action of SNP and 8-bromo-cGMP in inhibiting ouabain-sensitive Na+-K+-ATPase was mimicked by okadaic acid. Other studies have demonstrated that okadaic acid mimicked the action of SNP, atrial natriuretic peptide, and 8-bromo-cGMP in renal medulla in inhibiting ouabain-sensitive Na+-K+-ATPase, without affecting cGMP synthesis (Nathanson, unpublished observations). This interpretation is consistent with the presumed action of okadaic acid to bypass endogenous cGMP/PKG-dependent activation of the protein phosphatase inhibitors DARPP-32 and inhibitor 1 by inhibiting protein phosphatase directly (40, 45). Studies in the kidney have shown that DARPP-32 and inhibitor 1 are involved in the regulation of the Na+-K+-ATPase (3). Alternatively, okadaic acid could be blocking a protein phosphatase 2A in choroid plexus. The fact that okadaic acid works also implies that there is a basal kinase activity in the absence of added agonists in our experimental protocols.
It has been known for years that the luminal localization of Na+-K+-ATPase in choroid plexus epithelium plays a pivotal role in CSF production. The physiological implications for the role of the cholinergic-NOS system in choroid plexus are intriguing. Because cGMP-generating compounds and acetylcholine have the ability to decrease CSF production, this suggests that stimulation of cholinergic neurons and subsequent release of NO may decrease CSF production in part via inhibition of Na+-K+-ATPase activity.
NO's inhibition of Na+-K+-ATPase activity in
bovine choroid plexus epithelium may be more complex due to the
multiple Na+-K+-ATPase isoforms that exist in
this species (Ellis and Sweadner, unpublished observations). It should
be noted that the directionality of
Na+-K+-ATPase modulation by carbachol, SNP, and
other cGMP-generating agents may not be the same for all isoforms of
Na+-K+-ATPase, which are differentially
distributed among various tissues and species (43). For
example, it has been observed that in rat kidney, which also contains
the 1-isoform of the
Na+-K+-ATPase, SNP and cGMP cause inhibition of
the Na+-K+-ATPase (30). Studies
using mouse brain vessel endothelial cells, which express
Na+-K+-ATPase
1-,
2-, and
3-isoforms, have demonstrated
that the cGMP-induced inhibition of the
Na+-K+-ATPase is due mainly to the inhibition
of the
1-isoform (35). Other studies in rat
nervous system, which also expresses
Na+-K+-ATPase
1-,
2-, and
3-isoforms, show that
cGMP-generating agents caused a marked stimulation of the
Na+-K+-ATPase (20, 32). The
present studies also do not rule out parallel regulation of
Na+ transport through other mechanisms such as
bumetanide-sensitive K+ cotransport (25) or
Na+-H+ exchanger (31), which by
regulating Na+ entry to the cell may alter
Na+-K+-ATPase activity in intact tissue.
![]() |
ACKNOWLEDGEMENTS |
---|
This work was supported by National Institutes of Health Grants NS-27653 to K. J. Sweadner and EY-05077 to J. A. Nathanson.
![]() |
FOOTNOTES |
---|
Address for reprint requests and other correspondence: K. J. Sweadner, 149-6118 Massachusetts General Hospital, 149 13th St., Charlestown, MA 02129 (E-mail: sweadner{at}helix.mgh.harvard.edu).
The costs of publication of this article were defrayed in part by the payment of page charges. The article must therefore be hereby marked "advertisement" in accordance with 18 U.S.C. Section 1734 solely to indicate this fact.
Received 9 February 2000; accepted in final form 6 July 2000.
![]() |
REFERENCES |
---|
![]() ![]() ![]() ![]() ![]() ![]() ![]() |
---|
1.
Ames, AI,
Higashi K,
and
Nesbett FB.
Effects of PCO2, acetazolamide and ouabain on volume and composition of choroid plexus fluid.
J Physiol (Lond)
181:
516-524,
1965[ISI][Medline].
2.
Ames, AI,
Higashi K,
and
Nesbett FB.
Relation of potassium concentration in choroid plexus fluid to that in plasma.
J Physiol (Lond)
181:
506-515,
1965[ISI][Medline].
3.
Aperia, A,
Fryckstedt J,
Svensson L,
Hemmings HC, Jr,
Nairn AC,
and
Greengard P.
Phosphorylated Mr 32,000 dopamine- and cAMP-regulated phosphoprotein inhibits Na+,K(+)-ATPase activity in renal tubule cells.
Proc Natl Acad Sci USA
88:
2798-2801,
1991[Abstract].
4.
Bradbury, MW,
and
Davson H.
The transport of potassium between blood, cerebrospinal fluid and brain.
J Physiol (Lond)
181:
151-174,
1965[ISI][Medline].
5.
Brines, ML,
Gulanski BI,
Gilmore-Hebert M,
Greene AL,
Benz EJ, Jr,
and
Robbins RJ.
Cytoarchitectural relationships between ouabain binding and mRNA for isoforms of the sodium pump catalytic subunit in rat brain.
Brain Res Mol Brain Res
10:
139-150,
1991[ISI][Medline].
6.
Butt, E,
Eigenthaler M,
and
Genieser H-G.
(Rp)-8-pCPT-cGMPS, a novel cGMP-dependent protein kinase inhibitor.
Eur J Pharmacol
269:
265-268,
1994[Medline].
7.
Cumming, R,
Cheung WY,
Wallace RW,
and
Steiner AL.
Immunofluorescent localization of cyclic GMP, calmodulin and cyclic GMP-dependent protein kinase in the choroid plexus.
Neurosci Lett
22:
119-124,
1981[ISI][Medline].
8.
De Oliveria Elias, M,
Tavares de Lima W,
Vannuchi YB,
Marcourakis T,
daSilva ZL,
Trezena AG,
and
Scavone C.
Nitric oxide modulates Na+,K+ -ATPase activity through cyclic GMP pathway in proximal rat trachea.
Eur J Pharmacol
367:
307-314,
1999[ISI][Medline].
9.
Diodati, JG,
Quyyumi AA,
and
Keefer LK.
Complexes of nitric oxide with nucleophiles as agents for the controlled biological release of nitric oxide: hemodynamic effects in rabbit.
J Cardiovasc Pharmacol
22:
287-292,
1993[ISI][Medline].
10.
Edvinsson, L,
Nielsen KC,
and
Owman C.
Cholinergic innervation of choroid plexus in rabbits and cats.
Brain Res
63:
500-503,
1973[ISI][Medline].
11.
Ellis DZ, Nathanson JA, and Sweadner KJ. Role of nitric oxide and
cGMP in mediating Na,K-ATPase activity in secretory epithelium.
Excerpta Medica Int Congr Ser. In press.
12.
Esmann, M.
ATPase and phosphatase activity of Na+,K+- ATPase: molar and specific activity, protein determination.
Methods Enzymol
156:
105-115,
1988[ISI][Medline].
13.
Feron, O,
Dessy C,
Opel DJ,
Arstall MA,
Kelly RA,
and
Michel T.
Modulation of the endothelial nitric-oxide synthase-caveolin interaction in cardiac myocytes.
J Biol Chem
273:
30249-30254,
1998
14.
Fisone, G,
Snyder GL,
Aperia A,
and
Greengard P.
Na,K-ATPase phosphorylation in the choroid plexus: synergistic regulation by serotonin/protein kinase C and isoproterenol/cAMP-PK/PP-1 pathways.
Mol Med
4:
258-265,
1998[ISI][Medline].
15.
Fisone, G,
Snyder GL,
Fryckstedt J,
Caplan MJ,
Aperia A,
and
Greengard P.
Na,K-ATPase in the choroid plexus: regulation by serotonin/protein kinase C pathway.
J Biol Chem
270:
2427-2430,
1995
16.
Fotis, H,
Tatjanenko LV,
and
Vasilets LA.
Phosphorylation of the -subunits of the Na+/K+-ATPase from mammalian kidneys and Xenopus oocytes by cGMP-dependent protein kinase results in stimulation of ATPase activity.
Eur J Biochem
260:
904-910,
1999
17.
Furchgott, RF,
and
Vanhoutte PM.
Endothelium-derived relaxing and contracting factors.
FASEB J
3:
2007-2018,
1989
18.
Garthwaite, J,
Southam E,
Boulton CL,
Nielsen EB,
Schmidt K,
and
Mayer B.
Potent and selective inhibitor of nitric oxide-sensitive guanylyl cyclase by 1H-[1,2,4]oxadiazolo[4,3-a]quinoxalin-1-one.
J Pharmacol Exp Ther
48:
184-188,
1995.
19.
Gonzalez-Martinez, LM,
Avila J,
Marti E,
Lecuona E,
and
Martin-Vasallo P.
Expression of the -subunit isoforms of the Na,K-ATPase in rat embryo tissues, inner ear and choroid plexus.
Biol Cell
81:
215-222,
1994[ISI][Medline].
20.
Inada, H,
Shindo H,
Tawata M,
and
Onaya T.
cAMP regulates nitric oxide production and ouabain sensitive Na+,K+-ATPase activity in SH-SY5Y human neuroblastoma calls.
Diabetologia
41:
1451-1458,
1998[ISI][Medline].
21.
Johanson, CE.
Ventricles and cerebrospinal fluid.
In: Neuroscience in Medicine, edited by Conn MP.. Philadelphia: Lippincott, 1995, p. 171-196.
22.
Jørgensen, PL.
Isolation of (Na + K) ATPase.
Methods Enzymol
32:
277-290,
1974[Medline].
23.
Kase, H,
Iwahashi K,
Nakanishi S,
Matsuda Y,
Yamada K,
Takahashi M,
Murakata C,
Sato A,
and
Kaneko M.
K-252 compounds, novel and potent inhibitors of protein kinase C and cyclic nucleotide-dependent protein kinases.
Biochem Biophys Res Commun
142:
436-440,
1987[ISI][Medline].
24.
Keep, RF,
Xiang J,
and
Betz AL.
Potassium cotransport at the rat choroid plexus.
Am J Physiol Cell Physiol
267:
C1616-C1622,
1994
25.
Klarr, SA,
Ulanski LJ, 2nd,
Stummer W,
Xiang J,
Betz AL,
and
Keep RF.
The effects of hypo- and hyperkalemia on choroid plexus potassium transport.
Brain Res
758:
39-44,
1997[ISI][Medline].
26.
Lin, AYJ,
Szmydynger-Chodobska J,
Rahman H,
Mayer B,
Monfils PR,
Johanson CE,
Lim YP,
Corsetti S,
and
Chodobski A.
Immunohistochemical localization of nitric oxide synthase in rat anterior choroidal artery, stromal blood microvessels, and choroid plexus epithelial cells.
Cell Tissue Res
285:
411-418,
1996[ISI][Medline].
27.
Lindvall, M,
and
Owman C.
Autonomic nerves in the mammalian choroid plexus and their influence on the formation of cerebrospinal fluid.
J Cereb Blood Flow Metab
1:
245-266,
1981[ISI][Medline].
28.
Lowry, OH,
Rosebrough NJ,
Farr AL,
and
Randall RJ.
Protein measurement with the folin phenol reagent.
J Biol Chem
193:
265-275,
1951
29.
Malik, N,
Canfield V,
Sanchez-Watts G,
Watts AG,
Scherer S,
Beatty BG,
Gros P,
and
Levenson R.
Structural organization and chromosomal localization of the human Na,K-ATPase 3 subunit gene and pseudogene.
Mamm Genome
9:
136-143,
1998[ISI][Medline].
30.
McKee, M,
Scavone C,
and
Nathanson JA.
Nitric oxide, cGMP, and hormone regulation of active sodium transport.
Proc Natl Acad Sci USA
91:
12056-12060,
1994
31.
Murphy, VA,
and
Johanson CE.
Na+-H+ exchange in choroid plexus and CSF in acute metabolic acidosis or alkalosis.
Am J Physiol Renal Fluid Electrolyte Physiol
258:
F1528-F1537,
1990
32.
Nathanson, JA,
Scavone C,
Scanlon C,
and
McKee M.
The cellular Na+ pump as a site of action for carbon monoxide and glutamate: a mechanism for long-term modulation of cellular activity.
Neuron
14:
781-794,
1995[ISI][Medline].
33.
Nørby, JG.
Coupled assay of Na+,K+-ATPase activity.
Methods Enzymol
156:
116-119,
1988[ISI][Medline].
34.
Parmelee, JT,
Bairamian D,
and
Johanson CE.
Response of infant and adult choroid plexus potassium transporters to increased extracellular potassium.
Brain Res Dev Brain Res
60:
229-233,
1991[ISI][Medline].
35.
Pontiggia, L,
Winterhalter K,
and
Gloor SM.
Inhibition of Na,K-ATPase activity by cGMP is isoform-specific in brain endothelial cells.
FEBS Lett
436:
466-470,
1998[ISI][Medline].
36.
Ruiz, A,
Bhat SP,
and
Bok D.
Expression and synthesis of the Na,K-ATPase 2 subunit in human retinal pigment epithelium.
Gene
176:
237-242,
1996[ISI][Medline].
37.
Sato, T,
Kamata Y,
Irifune M,
and
Nishikawa T.
Inhibitory effect of several nitric oxide-generating compounds on purified Na,K-ATPase activity from porcine cerebral cortex.
J Neurochem
68:
1312-1318,
1997[ISI][Medline].
38.
Scavone, C,
Scanlon C,
McKee M,
and
Nathanson JA.
Atrial natriuretic peptide modulates sodium and potassium-activated adenosine triphosphatase through a mechanism involving cyclic GMP and cyclic GMP-dependent protein kinase.
J Pharmacol Exp Ther
272:
1036-1043,
1995[Abstract].
39.
Schindler, H,
Maier P,
Schroter E,
and
Cramer H.
Stimulation of cyclic GMP synthesis in the isolated choroid plexus of the rabbit by a muscarinic cholinergic mechanism and by sodium azide (Abstract).
Naunyn Schmiedebergs Arch Pharmacol
307:
R30,
1979[ISI].
40.
Snyder, GL,
Girault JA,
Chen JY,
Czernik AJ,
Kebabian JW,
Nathanson JA,
and
Greengard P.
Phosphorylation of DARPP-32 and protein phosphatase inhibitor-1 in rat choroid plexus: regulation by factors other than dopamine.
J Neurosci
12:
3071-3083,
1992[Abstract].
41.
Steardo, L,
and
Nathanson JA.
Brain barrier tissues: end organs for atriopeptins.
Science
235:
470-473,
1987[ISI][Medline].
42.
Sweadner, KJ.
Isozymes of the Na+/K+-ATPase.
Biochim Biophys Acta
988:
185-220,
1989[ISI][Medline].
43.
Sweadner, KJ.
Na,K-ATPase and its isoforms.
In: Neuroglia, edited by Kettenmann H,
and Ransom BR.. New York: Oxford University Press, 1995, p. 259-272.
44.
Szmydynger-Chodobska, J,
Monfils PR,
Lin AYJ,
Rahman MP,
Johanson CE,
and
Chodobski A.
NADPH-diaphorase histochemistry of rat choroid plexus blood vessels and epithelium.
Neurosci Lett
208:
179-182,
1996[ISI][Medline].
45.
Tsou, K,
Snyder GL,
and
Greengard P.
Nitric oxide/cGMP pathway stimulates phosphorylation of DARPP-32, a dopamine- and cAMP-regulated phosphoprotein, in the substantia nigra.
Proc Natl Acad Sci USA
90:
3462-3465,
1993[Abstract].
46.
Watts, AG,
Sanchez-Watts G,
Emanuel JR,
and
Levenson R.
Cell-specific expression of mRNAs encoding Na+,K+-ATPase -and
-subunit isoforms within the rat central nervous system.
Proc Natl Acad Sci USA
88:
7425-7429,
1991[Abstract].
47.
Zlokovic, BV,
Mackic JB,
Wang L,
McComb JG,
and
McDonough A.
Differential expression of Na,K-ATPase alpha and beta subunit isoforms at the blood-brain barrier and the choroid plexus.
J Biol Chem
268:
8019-8025,
1993