Immunohistochemical localization of Na+, K+-ATPase in the choroid plexus

Masuzawa, Toshio; Ohta, Toshiko; Kawamura, Masaru; Nakahara, Noboru; Sato, Fumiaki

doi:10.1016/0006-8993(84)90250-6

Cited by 82 publications

(44 citation statements)

References 23 publications

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“…In future work, it will be interesting to consider how depolarization, localized gradients of Na ϩ at the water channel vestibules, back-leak of Na ϩ , or other mechanisms involving activated AQP1 ion channels might contribute to the observed decrease in the net transport of fluid across the choroid plexus barrier in response to ANP. In the choroid plexus, unlike most epithelial cells, the Na ϩ -K ϩ -ATPase transporter is located in the apical membrane (Masuzawa et al, 1984) and provides the driving force for fluid secretion into the ventricle. Elevation of cGMP causes inhibition of Na ϩ -K ϩ -ATPase (Ellis et al, 2000), providing a logical mechanism for achieving decreased CSF production by downregulation of Na ϩ active transport.…”

Section: Discussionmentioning

confidence: 99%

Ion Channel Function of Aquaporin-1 Natively Expressed in Choroid Plexus

2006

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Aquaporins are known as water channels; however, an additional ion channel function has been observed for several including aquaporin-1 (AQP1). Using primary cultures of rat choroid plexus, a brain tissue that secretes CSF and abundantly expresses AQP1, we confirmed the ion channel function of AQP1 and assessed its functional relevance. The cGMP-gated cationic conductance associated with AQP1 is activated by an endogenous receptor guanylate cyclase for atrial natriuretic peptide (ANP). ; voltage insensitivity; and dependence on cGMP) matched properties characterized previously in AQP1-expressing oocytes. Background K ϩ and Cl Ϫ currents in the choroid plexus were dissected from AQP1 currents using Cs-methanesulfonate recording salines; the background currents recorded in physiological salines were not affected by AQP1-siRNA treatment. These results confirm that AQP1 can function as both a water channel and a gated ion channel. The conclusion that the AQP1-associated cation current contributes to modulating CSF production resolves a lingering concern as to whether an aquaporin ionic conductance can have a physiologically relevant function.

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Section: Discussionmentioning

confidence: 99%

Ion Channel Function of Aquaporin-1 Natively Expressed in Choroid Plexus

2006

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“…[117][118][119][120] Although these cells exhibit an apical distribution of this canonical basolateral protein, other proteins that serve as standard apical and basolateral markers retain their characteristic distributions.…”

Section: Cell-specific Variations In Traffickingmentioning

confidence: 99%

Trafficking to the Apical and Basolateral Membranes in Polarized Epithelial Cells

Stoops

Caplan

2014

Journal of the American Society of Nephrology

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Renal epithelial cells must maintain distinct protein compositions in their apical and basolateral membranes in order to perform their transport functions. The creation of these polarized protein distributions depends on sorting signals that designate the trafficking route and site of ultimate functional residence for each protein. Segregation of newly synthesized apical and basolateral proteins into distinct carrier vesicles can occur at the trans-Golgi network, recycling endosomes, or a growing assortment of stations along the cellular trafficking pathway. The nature of the specific sorting signal and the mechanism through which it is interpreted can influence the route a protein takes through the cell. Cell type-specific variations in the targeting motifs of a protein, as are evident for Na,K-ATPase, demonstrate a remarkable capacity to adapt sorting pathways to different developmental states or physiologic requirements. This review summarizes our current understanding of apical and basolateral trafficking routes in polarized epithelial cells.

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“…Na + K + ATPases localize to the ventricular surface of secretory brain epithelia in adult mammals and amphibia and are necessary for the secretion of CSF (Masuzawa et al, 1984;Saito and Wright, 1983). Thus, this gene family may be used at different times of development to initiate, and later maintain, ventricular fluid secretion.…”

Section: Atp1a1a1 Plays a Role In Lumen Inflationmentioning

confidence: 99%

Initial formation of zebrafish brain ventricles occurs independently of circulation and requires thenagie okoandsnakehead/atp1a1a.1gene products

2005

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The mechanisms by which the vertebrate brain develops its characteristic three-dimensional structure are poorly understood. The brain ventricles are a highly conserved system of cavities that form very early during brain morphogenesis and that are required for normal brain function. We have initiated a study of zebrafish brain ventricle development and show here that the neural tube expands into primary forebrain, midbrain and hindbrain ventricles rapidly, over a 4-hour window during mid-somitogenesis. Circulation is not required for initial ventricle formation, only for later expansion. Cell division rates in the neural tube surrounding the ventricles are higher than between ventricles and, consistently, cell division is required for normal ventricle development. Two zebrafish mutants that do not develop brain ventricles are snakehead and nagie oko. We show that snakehead is allelic to small heart, which has a mutation in the Na+K+ ATPase gene atp1a1a.1. The snakehead neural tube undergoes normal ventricle morphogenesis;however, the ventricles do not inflate, probably owing to impaired ion transport. By contrast, mutants in nagie oko, which was previously shown to encode a MAGUK family protein, fail to undergo ventricle morphogenesis. This correlates with an abnormal brain neuroepithelium, with no clear midline and disrupted junctional protein expression. This study defines three steps that are required for brain ventricle development and that occur independently of circulation: (1) morphogenesis of the neural tube, requiring nok function; (2) lumen inflation requiring atp1a1a.1function; and (3) localized cell proliferation. We suggest that mechanisms of brain ventricle development are conserved throughout the vertebrates.

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Immunohistochemical localization of Na+, K+-ATPase in the choroid plexus

Cited by 82 publications

References 23 publications

Ion Channel Function of Aquaporin-1 Natively Expressed in Choroid Plexus

Ion Channel Function of Aquaporin-1 Natively Expressed in Choroid Plexus

Trafficking to the Apical and Basolateral Membranes in Polarized Epithelial Cells

Initial formation of zebrafish brain ventricles occurs independently of circulation and requires thenagie okoandsnakehead/atp1a1a.1gene products

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