Expression of the β‐subunit isoforms of the Na, K‐ATpase in rat embryo tissues, inner ear and choroid plexus

González-Martínez, Luis M.; Ávila, Julio; Martı́, Elisa; Lecuona, Emilia; Martín‐Vasallo, Pablo

doi:10.1016/0248-4900(94)90003-5

Cited by 57 publications

(36 citation statements)

References 24 publications

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“…The assumption was that if CSF production is reduced, the bulk flow and re-absorption of CSF will also be reduced, leading to accumulation of protein. In accordance with this, rats from postnatal day 8 to adulthood showed an increase in the protein concentration in the CSF in response to acetazolamide, whereas no change was seen in newborn rats [10]. Based on these and later studies measuring the transfer of I 125 -albumin from blood into brain and CSF in newborn and juvenile rats it was concluded that CSF production was very low in the early postnatal period [1].…”

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confidence: 50%

“…NKAα 1 has not been previously investigated during early choroid plexus development, but the β 1 -and β 2 -subunits (which are part of the ATPase complex in the choroid plexus [10]) have been found by immunohistochemistry to be present in the rat lateral ventricular choroid plexus from E15 [10]. The function of the β-subunits is not entirely clear, but they are thought to be involved in insertion in the membrane.…”

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confidence: 97%

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Low levels of Na, K-ATPase and carbonic anhydrase II during choroid plexus development suggest limited involvement in early CSF secretion

Johansson

Dzięgielewska

Saunders

2008

Neuroscience Letters

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In the adult, cerebrospinal fluid (CSF) is produced by the actions of numerous transporters and enzymes creating ion gradients that drive the entry of water into the ventricles via the aquaporin-1 water channels (AQP1). It is not known when in development CSF secretion starts but, in the rat, it has been postulated to occur around the time of birth. However, recent evidence suggests that the secretion may start much earlier, as soon as the lateral choroid plexuses first appear (around E14).Purpose-To investigate the developmental profiles of two major enzymes responsible for CSF secretion in the adult, Na, K-ATPase (NKA) and carbonic anhydrase II (CAII).Methods-The developmental profiles of both enzymes were investigated using immunohistochemistry and Western Blot analysis in tissue from embryonic day (E) 15, 18, postnatal day (P) 0, 9 and adult rats.Result-Western Blot analysis showed low levels of NKA at E15 followed by a progressive increase with age. Immunohistochemistry confirmed the presence of NKA on the apical membrane of the lateral ventricular choroid plexus epithelium from E15 onwards. Western Blot analysis of CAII was complicated by its presence in blood, but the amount of protein increased with age. Immunohistochemically, CAII appeared in the lateral ventricular choroid plexus between P0 and P9.Conclusions-The low levels of NKA and CAII during early choroid plexus development indicate that other mechanisms, such as the previously described specific protein transfer across epithelial cells, may be involved in early CSF secretion and movement of water into the cerebral ventricles. KeywordsCerebrospinal fluid; Embryo; Brain development; Ventricular expansion; Epithelial cellsIn the adult, the majority of cerebrospinal fluid (CSF) is secreted into the cerebral ventricles by the epithelial cells of the four choroid plexuses [6]. A multitude of transporters and enzymes are responsible for the net movement of Na + , HCO 3− , Cl − and water from blood into CSF and a net movement of K + in the opposite direction [4]. The ion gradients thus formed drive the entry of water into the CSF, mainly through the aquaporin-1 water channels (AQP1 [4,22]). Two main enzymes involved in this process are Na, K-ATPase (NKA) and carbonic anhydrase II (CAII) and the inhibition of either result in significant reductions in CSF secretion rate [4].

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confidence: 97%

Low levels of Na, K-ATPase and carbonic anhydrase II during choroid plexus development suggest limited involvement in early CSF secretion

Johansson

Dzięgielewska

Saunders

2008

Neuroscience Letters

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“…The following antibodies were used: C464.6, a mouse monoclonal against ␣1 (1:30,000) from M. Kashgarian (Yale University); McB2, a mouse monoclonal against ␣2 (1:500) from K. Sweadner (Harvard University, Boston); in addition, two rabbit polyclonals against ␣2 and ␣3 from M. Caplan (see ref. 21); Ma3-915, a mouse monoclonal against ␣3 (1:1,000), and Ma3-930, a monoclonal against ␤1 from Affinity Bioreagents (Golden, CO): SpET-␤1, SpET-␤2, and SpET-␤3, rabbit polyclonals against ␤1, ␤2, and ␤3, respectively (1:20,000), from P. Martin-Vasallo (22,23). Two different antibodies for the ␥ modulator were used: one, labeled M-Ab, from R. Mercer (Washington University) made to the N terminus (outside), and one, labeled B-Ab, from R. Blostein (McGill University, Montreal) made to the C terminus (inside) of the ␥ modulator.…”

Section: Methodsmentioning

confidence: 99%

Na pump isoforms in human erythroid progenitor cells and mature erythrocytes

Hoffman

Wickrema

Potapova

et al. 2002

Proc. Natl. Acad. Sci. U.S.A.

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This study is aimed at identifying the Na pump isoform composition of human erythroid precursor cells and mature human erythrocytes. We used purified and synchronously growing human erythroid progenitor cells cultured for 7-14 days. RNA was extracted from the progenitor cells on different days and analyzed by RT-PCR. The results showed that only the ␣1, ␣3, ␤2, and ␤3 subunit isoforms and the ␥ modulator were present. Northern analysis of the erythroid progenitor cells again showed that ␤2 but not ␤1 or ␣2 isoforms were present. The erythroid cells display a unique ␤ subunit expression profile (called ␤-profiling) in that they contain the message for the ␤2 isoform but not ␤1, whereas leukocytes and platelets are known to have the message for the ␤1 but not for the ␤2 isoform. This finding is taken to indicate that our preparations are essentially purely erythroid and free from white cell contamination. Western analysis of these cultured progenitor cells confirmed the presence of ␣1, ␣3, (no ␣2), ␤2, ␤3, and ␥ together now with clear evidence that ␤1 protein was also present at all stages. Western analysis of the Na pump from mature human erythrocyte ghosts, purified by ouabain column chromatography, has also shown that ␣1, ␣3, ␤1, ␤2, ␤3, and ␥ are present. Thus, the Na pump isoform composition of human erythroid precursor cells and mature erythrocytes contains the ␣1 and ␣3 isoforms of the ␣ subunit, the ␤1, ␤2, and ␤3 isoforms of the ␤ subunit, and the ␥ modulator.

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“…mAb SM-GP50 has been shown to react with recombinant mouse ␤2 extracellular domain secreted from Chinese Hamster Ovary cells ; it worked well on blots and weakly on fixed tissue. Two polyclonal antibodies were raised against truncated proteins expressed in Escherichia coli encompassing the entire extracellular portions of human ␤1 or ␤2 (Gonzalez-Martinez et al, 1994); these are called SpETb1 and SpETb2, and both were used for staining fixed tissue and blots.…”

Section: Antibodies Usedmentioning

confidence: 99%

Isoforms of Na,K-ATPase α and β Subunits in the Rat Cerebellum and in Granule Cell Cultures

1997

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There are multiple isoforms of the Na,K-ATPase in the nervous system, three isoforms of the ␣ subunit, and at least two of the ␤ subunit. The ␣ subunit is the catalytic subunit. The ␤ subunit has several roles. It is required for enzyme assembly, it has been implicated in neuron-glia adhesion, and the experimental exchange of ␤ subunit isoforms modifies enzyme kinetics, implying that it affects functional properties. Here we describe the specificities of antibodies against the Na,K-ATPase ␤ subunit isoforms ␤1 and ␤2. These antibodies, along with antibodies against the ␣ subunit isoforms, were used to stain sections of the rat cerebellum and cultures of cerebellar granule cells to ascertain expression and subcellular distribution in identifiable cells. Comparison of ␣ and ␤ isoform distribution with doublelabel staining demonstrated that there was no preferential association of particular ␣ subunits with particular ␤ subunits, nor was there an association with excitatory or inhibitory neurotransmission modes. Isoform composition differences were seen when Purkinje, basket, and granule cells were compared. Whether ␤1 and ␤2 are specific for neurons and glia, respectively, has been controversial, but expression of both ␤ subunit types was seen here in granule cells. In rat cerebellar astrocytes, in sections and in culture, ␣2 expression was prominent, yet the expression of either ␤ subunit was low in comparison. The complexity of Na,K-ATPase isoform distribution underscores the subtlety of its regulation and physiological role in excitable cells.

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Expression of the β‐subunit isoforms of the Na, K‐ATpase in rat embryo tissues, inner ear and choroid plexus

Cited by 57 publications

References 24 publications

Low levels of Na, K-ATPase and carbonic anhydrase II during choroid plexus development suggest limited involvement in early CSF secretion

Low levels of Na, K-ATPase and carbonic anhydrase II during choroid plexus development suggest limited involvement in early CSF secretion

Na pump isoforms in human erythroid progenitor cells and mature erythrocytes

Isoforms of Na,K-ATPase α and β Subunits in the Rat Cerebellum and in Granule Cell Cultures

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