共查询到20条相似文献,搜索用时 15 毫秒
1.
2.
H. H. Bodemann 《Journal of molecular medicine (Berlin, Germany)》1981,59(24):1333-1343
Zusammenfassung Diese Übersicht beschreibt die Eigenschaften der Na+, K+-ATPase bzw. der Na+, K+-Pumpe in der intakten Membran und die hochspezifische Hemmung dieses Transportenzyms durch Herzglykoside.Es wird auf die Wechselwirkung zwischen Glykosid und Enzym eingegangen und da bei insbesondere auf die Steuerung der Glykosidbindung durch ATP, K+, Na+, Mg2+ und Ca2+.Die Bedeutung des Enzyms als wahrscheinlicher pharmakologischer Rezeptor für Herzglykoside wird herausgestellt. Zunächst erfolgt eine Beschreibung der Schwierigkeiten und Fortschritte bei der Herstellung eines Zusammenhanges zwischen positiv inotropem Effekt von Herzglykosiden und deren Bindung an die Na+, K+-Pumpen des Herzmuskels bzw. der Hemmung des Transportsystems durch Herzglykoside.Es werden neuere Erkenntnisse über die Verknüpfung von der Hemmung der Na+, K+-Pumpe, die zu einer Erhöhung der intrazellulären Na+-Konzentration führt, und der indirekten Erhöhung der intrazellulären Ca2+-Aktivität referiert.Mitteilungen über den Nachweis einer herzglykosidartigen endogenen Aktivität entsprechen der hohen Rezeptorspezifität für Herzglykoside. 相似文献
3.
Toshikatsu Shimizu Koji Yoshitomi Junichi Taniguchi Masashi Imai 《Pflügers Archiv : European journal of physiology》1989,414(5):500-508
Morphological studies have demonstrated that a chronic increase in distal Na+ delivery causes hypertrophy of the distal convoluted tubule (DCT). To examine whether high NaCl-intake also causes functional changes in the well defined DCT, we measured transmural voltage (V
T), lumen-to-bath Na+ flux (J
Na(LB)), and net K+ secretion (J
K(net)) in DCTs obtained from control rabbits and those on high NaCl-intake diets. The lumen negativeV
T was significantly greater in the high NaCl group than in the control group. The net K+ secretion (pmol mm–1 min–1) was greater in the high NaCl-intake group (54.1±13.0 vs 14.7±5.6). The K+ permeabïlities in both luminal and basolateral DCT membranes, as assessed by the K+-induced transepithelial voltage deflection inhibitable with Ba2+, were increased in the experimental group. The lumen-to-bath22Na flux (pmol mm–1 min–1) was also greater in the experimental group (726±119 vs 396±65). TheV
T component inhibitable with amiloride was also elevated in the high NaCl-intake group. Furthermore, Na+–K+-ATPase activity of the DCT was higher in the experimental than in the control group. We conclude that high NaCl intake increases both Na+ reabsorption and K+ secretion by the DCT. This phenomenon is associated with an increased Na+–K+-ATPase activity along with increased Na+ and K+ permeabilities of the luminal membrane, and an increase in the K+ permeability of the basolateral membrane. Cellular mechanisms underlying these functional changes remain to be established. 相似文献
4.
N. G. Svitasheva E. E. Kalish N. S. Logvinenko E. I. Solenov 《Bulletin of experimental biology and medicine》1992,114(2):1113-1117
Laboratory of Physiological Genetics, Institute of Cytology and Genetics, Siberian Brach, Russian Academy of Sciences, Novosibirsk. (Presented by Academician of the Russian Academy of Medical SciencesV. P. Lozov.) Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 114, No. 8, pp. 150–153, August, 1992. 相似文献
5.
Na+, K+-ATPase is one of major membrane proteins that has two subunits, alpha and beta. The alpha subunit has the ATPase activity and the ouabain binding site. Among four isoforms of the alpha subunit, expression of alpha1, alpha2, and alpha3, but not alpha4, is observed in matured rat brain. Ouabain is one of cardiac glycosides, and endogenous ouabain-like compounds have been recognized as a new class of steroid hormone. The alpha subunit is considered as their endogenous receptor. Recent studies envisaged the importance of membrane microdomains (MDs) as signaling platforms, which are recovered as a detergent-resistant membrane microdomain fraction (DRM). Although this ATPase has been considered as a non-DRM protein, some amount of the alpha subunit was found to be a component of the DRM prepared from the synaptic plasma membrane fraction (SPM) of rat brain. Ouabain treatment increased the amount of alpha3 isoform, but not alpha1, in the DRM derived from synaptosome fraction and SPM. These results suggest that the localization of the alpha subunit of Na+, K+-ATPase is regulated with isoform-specific mechanisms and the physiological importance of DRM in the signal transduction of the endogenous ouabain-like steroid hormone in neurons. 相似文献
6.
Barry Chantrelle Martin G. Cogan Floyd C. Rector Jr. 《Pflügers Archiv : European journal of physiology》1982,395(3):186-189
Recent in vitro studies from the rat and rabbit have suggested a tightly coupled sodium/hydrogen ion exchanger on the luminal membrane of proximal tubules. The steep sodium gradient from the lumen to cell supplies indirect energy for hydrogen ions to be pumped from the cell to the lumen. However, a proton translocating pump has been demonstrated in other epithelia, which is independent of sodium transport and directly driven by ATP. To examine the role that sodium might play in the process of acidification, rat proximal convoluted tubules and their surrounding peritubular capillaries were perfused in vivo with artificial ultrafiltrate-like perfusion solutions. Total CO2 absorption was measured by microcalorimetry during alterations in sodium transport by replacement of the sodium with an impermeant cation, choline, or by inhibition of the (Na++K+)-ATPase by removing potassium from both perfusion solutions. Under control conditions the absolute rate of total CO2 absorption was 140 pmol/mm·min. In the choline substitution and potassium removal experiments, absolute total CO2 absorption fell to 23 and 28 pmol/mm·min, respectively. The data suggest that: 1) in the rat superficial proximal convoluted tubule approximately 80% of the bicarbonate absorption is tightly coupled to sodium transport; 2) this process is driven indirectly by the (Na++K+)-ATPase system; and 3) the residual 20% of acidification appears to be mediated by another mechanism or may be a consequence of technical liminations. 相似文献
7.
Adrian I. Katz Harry K. Genant Barbara L. Corsaw 《Pflügers Archiv : European journal of physiology》1971,330(2):136-148
Summary The role of renal Na+–K+-ATPase in the acute changes in sodium reabsorption caused by isotonic volume expansion was evaluatedin vivo andin vitro in the rat and the dog. Duringin vivo volume expansion with isotonic saline in the rat, renal medullary Na+–K+-ATPase specific activity increased, while the simultaneously determined cortical Na+–K+-ATPase specific activity and kinetics remained unchanged. Furthermore, experimentsin vitro failed to demonstrate a circulating inhibitor of renal Na+–K+-ATPase both in plasma dialysates from volume-expanded rats and in plasma dialysates concentrated 20-fold by ultrafiltration from volume-expanded dogs. These results suggest that the decreased proximal tubular reabsorption of sodium during volume expansion is not mediated by inhibition of renal cortical Na+–K+-ATPase. The acute increment in medullary Na+–K+-ATPase observed could represent an adaptive response to increased sodium reabsorption by the loops of Henle, and raises the possibility that this enzyme may participate in relatively rapid adjustments in the transport of sodium by the renal tubule. 相似文献
8.
Teleost fish are able to regulate their energy intake selecting from pure macronutrients sources, but the regulatory mechanisms involved in macronutrients selection remain unknown. Serotonin (5-HT) reduces food intake in mammals and fish and modifies the macronutrients selection pattern in mammals; however, no information is available about its role on macronutrients selection in fish. The aim was to determine the effect of orally administered 5-HT (0.1, 0.5 and 2.5 mg kg BW(-)(1)) into gelatine capsules on the subsequent macronutrient selection of sea bass, using for this purpose gelatine capsules including carbohydrates, protein, or lipids separately. The voluntary ingested 5-HT was released into the plasma of fish, reaching a level two times greater than the controls, 45 min after the ingestion of a capsule containing 2.5 mg kg BW(-1) of 5-HT. The indoleamine, at doses of 0.1, 0.5 and 2.5 mg kg BW(-1), produced a reduction in total food intake of 31%, 49% and 37%, respectively, compared to the baseline, modifying the macronutrient selection pattern. The percentage of fat selected was significantly reduced whereas the percentage of protein significantly increased after administration of highest dose, but no changes were observed in the proportion of carbohydrate for any 5-HT doses. In conclusion, oral administration of 5-HT affected both amount of food intake and pattern of macronutrients selected. This is the first evidence supporting a role of 5-HT as a neurohumoral mediator involved in macronutrients selection in fish. 相似文献
9.
Akimova OA Pchejetski D Hamet P Orlov SN 《Pflügers Archiv : European journal of physiology》2006,451(4):569-578
The signaling cascade resulting in the death of several types of cells treated with ouabain or other cardiotonic steroids (CTS) remains poorly understood. Recently, we observed that ouabain kills epithelial and endothelial cells via its interaction with Na+, K+ -ATPase, but independently of inhibition of Na+, K+ -ATPase-mediated ion fluxes and inversion of the [Na+]i/[K+]i ratio. Here, we report that the death of ouabain-treated epithelial cells from the Madin-Darby canine kidney (C7-MDCK) and endothelial cells from porcine aortae is suppressed by acidification of medium from pH 7.4 to 7.0, i.e. under conditions when pHi was decreased from 7.2 to 6.9. The rescue of ouabain-treated C7-MDCK cells was also detected under selective intracellular acidification caused by inhibition of Na+/H+ exchanger. In these cells, neither Na+, K+ pump activity nor [3H]-ouabain binding was significantly affected by modest acidification. The death of ouabain-treated cells was independent of inhibition of RNA and protein synthesis with actinomycin D and cycloheximide. In contrast, both compounds sharply attenuated the protective action of acidified medium. Thus, our results show that very modest intracellular acidification is sufficient to inhibit the Na+ i/K+ i-independent death signal triggered in epithelial and endothelial cells by CTS. They also suggest that the protective action of acidification is mediated by de novo expression of genes involved in inhibition of the cell death machinery. 相似文献
10.
Activity of (Na+K+)-stimulated adenosintriphosphatase in the rat nephron 总被引:11,自引:0,他引:11
Summary In 17 male Wistar rats in antidiuresis 10 different nephron segments and arteries are identified with the aid of Lowry's technique, dissected and total-and (Mg++)-adenosintriphosphatase (=ATPase) determined. (Na+K+)-activated ATPase in the distal tubule is four to five times (max. eight times) more active than in the proximal segment. This difference of activity may speak for a high pump mechanism mediated by the way of a (Na+K+)-activated enzyme system in the distal nephron and for a partially passive reabsorption of sodium from the proximal convolution.With the support of the Schweiz. Nationalfonds zur Förderung der wissenschaftlichen Forschung (Nr. 4256 and Nr. 4809.3) 相似文献
11.
Na+, K+-ATPase and Mg2+-ATPase activities were studied in neurons and glial cells of the olfactory cortex of the rat by quantitative cytophotometry
in conditions of long-term potentiation (LTP), and significant changes in direction and extent were found. Na+, K+-ATPase activity decreased in neurons in the first 15 min after LTP, with subsequent elevation by 30 min. Mg2+-ATPase activity remained unchanged in these conditions. Glial cells showed significant increases in Na+, K+-ATPase activity in the initial period after LTP, with return to control by 30 min. Again, there were no significant changes
in Mg2+-ATPase activity. The formation and persistence of LTP in neurons and glial cells was accompanied by significant changes in
Na+, K+-ATPase activity, which were reciprocal in nature.
Functional Neurochemistry Laboratory (Director N. A. Emel'yanov), I. P. Pavlov Institute of Physiology, Russian Academy of
Sciences, St. Petersburg. Translated from Fiziologicheskii Zhurnal im. I. M. Sechenova, Vol. 81, No. 3, pp. 16–20, March,
1995. 相似文献
12.
Luciano K. Jornada Samira S. Valvassori Camila O. Arent Daniela Leffa Adriani A. Damiani Giana Hainzenreder Camila L. Ferreira Morgana Moretti Vanessa M. Andrade João Quevedo 《Neuroscience letters》2010
There is an emerging body of data suggesting that bipolar disorder is associated with DNA damage. Intracerebroventricular (ICV) administration of ouabain in rats results in manic-like alterations. We evaluated DNA damage of peripheral blood, cerebrospinal fluid and hippocampus of rats after ICV ouabain injection. Ouabain-induced hyperlocomotion was examined in an open field. Additionally, we used single cell gel electrophoresis (comet assay) to measure early transient damage in cerebrospinal fluid (CSF), hippocampus and blood; and the micronucleus test to measure persistent damage in total blood samples of rats after ouabain administration. Our findings demonstrated that ouabain induced hyperlocomotion in rats, and this response remained up to 7 days following a single ICV injection. In addition, we observed that the persistent increase in the rat spontaneous locomotion is associated with increased hippocampal and peripheral index of early DNA damage in rats. No significant alterations were observed in the micronucleus frequency in total blood samples of the rats after the ouabain ICV injection. These results suggest that ouabain may induce peripheral and central early DNA damage, but this early damage may be repaired. 相似文献
13.
Alain dit Philippe Bidie Ernest Koffi Jean-David N'Guessan Allico Joseph Djaman Fr��d��rique Guede-Guina 《African journal of traditional, complementary, and alternative medicines》2008,5(3):294-301
Mitragyna ciliata (MYTA) (Rubiaceae) inhibits plasmodia activity. MYTA induces a cardiotonicity of the digitalic type on rat''s isolated heart. In this work we studied the effect of MYTA on microsomal Na+/K+ dependant ATPase (Na+, K+ ATPase) extracted from the heart of a rabbit since digitalics inhibit Na+, K+ ATPase. Our results revealed that the Na+/K+ ATPase has an optimum pH of 7.4 and temperature of 37°C respectively. There is a linear relationship between the organic phosphate formed and the incubation time over 25 mins incubation period. The ATP hydrolysis rate in the presence of MYTA was 0.775 µM/min. LINEWEAVER and BURK plots showed that MYTA did not alter KM (1.31 mM) but decreased VMAX. This study shows that MYTA exerts a non-competitive inhibition on the microsomal Na+/K+ ATPase extracted from rabbit heart with a Ci50 of 48 µg / ml. We conclude that the mechanism of action of MYTA is linked to the inhibition of the Na+/K+ ATPase like cardiotonics of the digitalic type. 相似文献
14.
Yuji Fujita MSc Takatosi Kakuta MD PhD Manabu Asano MD Johbu Itoh PhD Katuhiro Sugano MD Naoko Kagiwada MD Takayuki Tokimasa MD PhD Akira Saito MD 《Journal of artificial organs》2000,3(2):107-111
We intend to develop a bioartificial kidney using tubular epithelial cells and artificial membranes, and to evaluate the reabsorptive
function of the confluent layers. Madin-Darby canine kidney (MDCK) cells were cultured on a nucleopore polycarbonate membrane
for up to 4 weeks after confluence to examine the influence of culture period on their properties, such as the localization
of Na+/K+-ATPase and active Na+ transport. The results were as follows. Ouabain-sensitive Na+ active transport declined at 3 to 4 weeks after confluence in each matrix. The localization of Na+/K+-ATPase indicated depolarization in the cell membrane 3 to 4 weeks after confluence. Prolongation of the culture period increased
the formation of an upheaving cell mass after the formation of the confluent monolayer. Scanning electron microscopy revealed
fewer microvilli and more flat cells after 3 to 4 weeks of confluency. We conclude that the decline of Na+ active transport in the MDCK cells was due to both the formation of multilayers and a decline of cell function throughout
the long period of culture following the formation of the confluent monolayers. Further study for selection of membrane material,
the extracellular matrix, and species of cells should be continued.
Laboratories for Structure and Function Research
Department of Physiology 相似文献
15.
Philine Wangemann Daniel C. Marcus 《Pflügers Archiv : European journal of physiology》1989,414(6):656-662
Transitional cells of the crista ampullaris were impaled with microelectrodes in order to record the membrane potential (PD) and to investigate membrane properties. In control solution the PD was –87±1 mV (n=103). This value is not significantly different from –83±2 mV (n=24) measured in Cl– free solution. [Cl–] steps from 150 to 15 mmol/l (n=24) depolarized the membrane by about 2 mV, indicating a minor Cl– conductance. The transference number for K+ was 0.75±0.01 (n=79) obtained from the PD responses to K+ steps from 3.6 to 25 mmol/l. The cell membrane depolarized and the amplitude of PD responses to [K+] steps was reduced by Ba2+ (2·10–6 to 10–3 mol/l), quinidine (10–3 mol/l), quinine (10–3 mol/l), Rb+ (20 mmol/l), Cs+ (20 mmol/l), NH4
+ (20 mmol/l) and Tl+ (0.5 mmol/l), whereas tetraethylammonium (TEA, 20 mmol/l) had no effect. The dose-response curve for Ba2+ in the presence of 3.6 mmol/l K+ was shifted to the right by approximately three decades in the presence of 25 mmol/l K+ and by a factor of about 4 in the presence of 135 mmol/l gluconate as a substitute for Cl–. Transitional cells were depolarized by ouabain, suggesting the presence of (Na++K+-ATPase.This work was supported by grants from the Deafness Research Foundation to PhW and the National Institute of Health (NS 19490) to DCM 相似文献
16.
T. Iwaoka T. Umeda M. Ohno J. Inoue S. Naomi T. Sato I. Kawakami 《Journal of molecular medicine (Berlin, Germany)》1988,66(16):724-728
Summary The effects of low and high NaCl diets on plasma glucose and insulin responses to glucose ingestion were investigated in 15 patients with essential hypertension. Oral glucose (75 g) tolerance tests were carried out while patients were taking diets with low (2 g/day) and high (20 g/day) NaCl content. Fasting plasma glucose and insulin levels were both significantly lower during ingestion of the high NaCl diet (p<0.05). After glucose ingestion, the incremental areas under the two hour plasma glucose and insulin curves were significantly smaller during ingestion of the high NaCl diet (glucosep<0.005 and insulinp<0.025). These findings that low NaCl diets increase the glycemic response to glucose loads suggest that use of NaCl restriction for the treatment of essential hypertension may not always be desirable.Abbreviations Na+, K+-ATPase
sodium, potassium adenosinetriphosphatase
- SEM
standard error of the mean 相似文献
17.
《Journal of neurogenetics》2013,27(1):53-63
Abstract: the distinct localization of membrane proteins with regard to cell polarity is crucial for the structure and function of various organs in multicellular organisms. However, the molecules and mechanisms that regulate protein localization to particular subcellular domains are still largely unknown. To identify the genes involved in regulation of protein localization, the authors performed a large-scale screen using a Drosophila RNA interference (RNAi) library, by which Drosophila genes could be knocked down in a tissue- and stage-specific manner. Drosophila photoreceptor cells have a morphologically distinct apicobasal polarity, along which Chaoptin (Chp), a glycosylphosphatidylinositol (GPI)-anchored membrane protein, and the Na + , K+ -ATPase are localized to the apical and basolateral domains, respectively. By examining the subcellular localization of these proteins, the authors identified 106 genes whose knockdown resulted in mislocalization of Chp and Na+ , K+ -ATPase. Gene ontology analysis revealed that the knockdown of proteasome components resulted in mislocalization of Chp to the basolateral plasma membrane. These results suggest that the proteasome is involved, directly or indirectly, in selective localization of Chp to the apical plasma membrane of Drosophila photoreceptor cells. 相似文献
18.
Training in inhibitory avoidance causes a reduction of Na+,K+-ATPase activity in rat hippocampus 总被引:2,自引:0,他引:2
Wyse AT Bavaresco CS Reis EA Zugno AI Tagliari B Calcagnotto T Netto CA 《Physiology & behavior》2004,80(4):475-479
Compelling evidence has indicated the involvement of Na(+),K(+)-ATPase in the mechanisms of synaptic plasticity. In the present study, we investigated the effect of inhibitory avoidance training on Na(+),K(+)-ATPase activity, at different times after training, in the rat hippocampus. Male adult Wistar rats were trained in a step-down inhibitory avoidance task and compared to those submitted to isolated footshock (0.4 mA) or placed directly onto the platform. Na(+),K(+)-ATPase activity decreased, by 60%, in hippocampus of rats sacrificed immediately after the isolated footshock, as well as immediately (0 min) and 6 h after training; this effect was not present 24 h after training. We also verified that enzyme activity was not altered in rats killed after just being on the platform. These findings suggest that Na(+),K(+)-ATPase activity may be involved in the memory consolidation of step-down inhibitory avoidance in the hippocampus. 相似文献
19.
Caroline M. Mason Mark A. Jepson Nicholas L. Simmons Barry H. Hirst 《Pflügers Archiv : European journal of physiology》1994,427(3-4):343-347
Na+, K+-ATPase expression in the epithelia of rabbit gut-associated lymphoid tissue was measured using indirect immunofluorescence
and confocal laser scanning microscopy. All four major sites of aggregated lymphoid tissue, i. e. Peyer's patch, sacculus
rotundus, caecal patch and appendix, were studied. Na+, K+-ATPase expression was localized to the basolateral surface of cells of the follicle-associated epithelium (FAE) and adjacent
villous or surface epithelia (non-FAE), where increased expression during enterocyte migration was evident. In the FAE, expression
of Na+, K+-ATPase appeared to be lower in the specialized M cells than in enterocytic-type cells, although expression in both cell types
was lower than in adjacent non-FAE. Quantification of immunofluorescent staining of Na+, K+-ATPase by confocal laser scanning imaging showed a reduction of expression in the FAE to approximately 20–60% relative to
that in the adjacent non-FAE. These results are consistent with a primary role of the FAE in mucosal immunity with minimal
involvement in active solute absorption. 相似文献
20.
We investigated mechanisms of regulatory volume increase in fused Madin-Darby canine kidney (MDCK) cells, a cell line originally derived from renal collecting duct. The intracellular ion concentrations as well as the concentration of the volume marker tetramethylammonium+ were measured by means of ion-selective microelectrodes. Application of hypertonic Ringer bicarbonate solution (+150 mmol/l mannitol) resulted in cell shrinkage to 84±2% of the initial cell volume (shrinkage expected for an ideal osmometer = 66%), indicating a significant regulatory volume increase. During the first 90 s of the hypertonic stress, a transient increase in intracellular Na+ and HCO
3
–
concentrations was observed. It was followed by a sustained increase in intracellular K+ and Cl– concentrations. Ouabain (0.1 mmol/l) as well as amiloride (1 mmol/l) reduced K+ accumulation significantly, whereas the H+ /K+-ATPase inhibitor SCH 28080 had no effect. Hypertonic stress hyperpolarized the cell membrane potential by 19±2 mV, owing to the decrease of the ratio of Cl– conductance to K+ conductance of the cell membrane. We conclude: (a) acute hypertonic stress activates Na+/H+ exchange in MDCK cells; (b) transient alteration of intracellular Na+ and pH stimulates Na+/K+-ATPase and Cl–/HCO
3
–
exchange, both leading to the sustained intracellular accumulation of KCl; (c) a high intracellular KCl concentration is maintained by the partial reversion of the Cl–/K+ conductance ratio of the plasma membrane. 相似文献