• The Korean Journal of Physiology and Pharmacology
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• v.17 no.4
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• pp.275-281
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• 2013

Astrocytes are reported to have critical functions in ischemic brain injury including protective effects against ischemia-induced neuronal dysfunction. Na-K ATPase maintains ionic gradients in astrocytes and is suggested as an indicator of ischemic injury in glial cells. Here, we examined the role of the Na-K ATPase in the pathologic process of ischemic injury of primary cultured astrocytes. Chemical ischemia was induced by sodium azide and glucose deprivation. Lactate dehydrogenase assays showed that the cytotoxic effect of chemical ischemia on astrocytes began to appear at 2 h of ischemia. The expression of Na-K ATPase ${\alpha}1$ subunit protein was increased at 2 h of chemical ischemia and was decreased at 6 h of ischemia, whereas the expression of ${\alpha}1$ subunit mRNA was not changed by chemical ischemia. Na-K ATPase activity was time-dependently decreased at 1, 3, and 6 h of chemical ischemia, whereas the enzyme activity was temporarily recovered to the control value at 2 h of chemical ischemia. Cytotoxicity at 2 h of chemical ischemia was significantly blocked by reoxygenation for 24 h following ischemia. Reoxygenation following chemical ischemia for 1 h significantly increased the activity of the Na-K ATPase, while reoxygenation following ischemia for 2 h slightly decreased the enzyme activity. These results suggest that the critical time for ischemia-induced cytotoxicity of astrocytes might be 2 h after the initiation of ischemic insult and that the increase in the expression and activity of the Na-K ATPase might play a protective role during ischemic injury of astrocytes.

• Biomolecules & Therapeutics
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• v.5 no.3
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• pp.228-232
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• 1997

AU-164 was synthesized as a reversible gastric $H^+/K^+$ ATPase inhibitor, and its effects were tested in various systems. AU-164 inhibited rabbit gastric $H^+/K^+$ ATPase with an $IC_{50}$/ of 9 $\mu$M. On the other hand, AU-164 was a weak inhibitor for dog kidney $Na^+/K^+$ ATPasc, indicating the selectivity for gastric $H^+/K^+$ ATPase. The reversible property of the AU-164-induced inhibition of $H^+/K^+$ ATPase was confirmed by filtering the inhibition mixture through Sephadex G-25M column. In vivo basal acid secretion was also inhibited by AU-164 under the pylorus ligation of Sprague-Dawley rats. In addition, AU-164 protected dose dependently gastric lesion induced by ethanol in rats. The $ED_{50}$ value of 62 mg/kg p.o was estimated. These results suggest that AU-164 is a potent, selective and reversible gastric $H^+/K^+$ ATPase inhibitor, and that AU-164 has a potential use for the clinical therapeutics of peptic ulcer disease.

• The Korean Journal of Physiology
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• v.7 no.1
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• pp.41-47
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• 1973

$Na^{+}$ balance was studied in Rana temporaria, which hibenates in fresh water in the winter time. $Na^{+}$ uptake rate, skin $Na^{+}$ loss rate, urinary $Na^{+}$ loss rate and $Na^{+}-K^{+}$ adenosine triphosphatase(ATPase) were measured at two different temperatures $1{\sim}2^{\circ}C\;and\;20{\sim}24^{\circ}C$ respectively. The results obtained were as follows: 1. $Na^{+}$ uptake rates in the frog in an artificial Pond water (APW) were found to be $8.28{\pm}0.73\;and\;2.19{\pm}0.37\;{\mu}Eq/g/day\;at\;20{\sim}24^{\circ}C\;and\;1.0{\sim}2.5^{\circ}$ respectively. 2. $Na^{+}$ loss rate through the frog skin to APW were found to be $4.26{\pm}0.72\;and\;0.93{\pm}0.21\;{\mu}Eq/g/day$ at the same temperatures. 3. Mean rates of urinary $Na^{+}$ loss at $20{\sim}24^{\circ}C\;and\;3{\sim}4^{\circ}C$ were found to be $3.02{\pm}0.73\;and\;0.78{\pm}0.13\;{\mu}Eq/g/day$ respectively. 4. The activities of $Na^{+}-K^{+}$ activated ATPase of frog skin fragments were found to be $258{\pm}39.4\;and\;49.6{\pm}7.1\;{\mu}M\;Pi/g$ protein/hr at $24^{\circ}C\;and\;2^{\circ}C$ respectively. From the above results, it may be concluded that frogs can take up enough $Na^{+}$ through the skin from APW exceeding skin loss Plus urinary loss at $1{\sim}2^{\circ}C$. It is suggested that $Na^{+}$ transport across frog skin is closely related with $Na^+-K^+$ ATPase since $Q_{10}\;of\;Na^{+}$ uptake is much similar to that of the activities of $Na^{+}-K^{+}$ ATPase.

• The Korean Journal of Zoology
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• v.23 no.2
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• pp.61-68
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• 1980

Quantitative analysis of the activities of transport ATPases as well as alkaline phosphatase of the mouse uterus was carried out during the estrous cycle. Even though the proportional patterns of the enzyme activities were similar each another between the stages of estrous cycle, the absolute activities of the enzymes except $K^+$-dependent and $Na^+$, $K^+$-activated ATPases at the time of estrus were significantly (p<0.025) higher than that at any other time of the estrous cycle. That is, the activities of $K^+$-dependent and $Na^+$, $K^+$-activated ATPases were negligible during the period of time from diestrus to estrus while the little activities (0.04 $\\sim$ 0.05$\\mu$M/mg protein/hr in average, $6\\sim7$% of the total enzyme activity) of these enzymes appeared at the time of metaestrus. On the other hand, at the time of estrus, the activities of $Mg^++$-dependent phosphatase, transport ATPase and alkaline phosphatase were rapidly and tremendously increased to be 0.69 (35%), 0.42 (21%) and 1.58 (79%), respectively. The activity of alkaline phosphatase was in the range of 0.60 $\\sim$ 1.58 (79 $\\sim$ 90%) and predominant throughout the estrous cycle. The activity of $Mg^++$-dependent alkaline phosphatase was estimated as 12 $\\sim$ 16% of the total enzyme activity. Therefore, it is assumed likely that $K^+$-dependent and $Na^+$, $K^+$-activated ATPases are not the main factors to control the fluid accumulation at the time of estrus, but may be the factors to reabsorb the luminal fluid into the uterine epithelium at the time of metaestrus, and that $Mg^++$-dependent phosphatase, transport ATPase and alkaline phosphatase must be closely involved in the secretion of luminal fluid from the epithelial cells of the mouse uterus.

• Journal of Environmental Health Sciences
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• v.24 no.3
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• pp.18-21
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• 1998

Bromobenzene 투여에 의한 간조직중 ATPase 활성을 관찰할 목적으로 흰쥐에 bromobenzene을 체중 kg당 400 mg을 복강으로 투여한 다음 4시간 후에 처치하여 다음과 같은 결과를 얻었다. Bromobenzene 투여로 인한 체중당 간무게는 유의하게 증가되었으나 간조직중 단백질 함량은 감소되었다. 혈청중 alanine aminotransferase 활성은 대조군과 별다른 차이를 볼수 없었다. 따라서 본 실험조건에서 Bromobenzene 처치 실험동물에서 간조직은 가역적상해로 생각되며 이러한 실험동물모델에 $Na^+/K^+$-ATPase 활성은 유의하게 (p<0.05)증가되었으며 이때 V$_{max}$ 치역시 대조군에 비하여 증가 되었다. 이때 간조직중 glutathione 함량은 감소되었으며 glutathione S-transferase 활성 및 cytochrome P-450 함량치는 증가되는 경향을 보였다.

• The Korean Journal of Physiology
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• v.17 no.1
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• pp.55-61
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• 1983

Effects of SITS (4-acetamido-4'-isothiocyano-2, 2'-disulfonic stilbene) on a $Na^+$ transport, tissue oxygen consumption and Na-K-ATPase activity were studied in isolated frog skin preparations. $Na^+$ transport was estimated by measuring the short-circuit current(SC) across the skin; oxygen consumption was measured in separated epidermis as well as in intact skin; and Na-K-ATPase was assayed in $24,000{\times}g$ fraction of epidermal homogenates. The SCC across the skin Was rapidly and substantially reduced in the presence of 10 mM SITS in the medium bathing the outside(mucosal) surface of the skin. When the drug was added to the inside(serosal) bathing medium, there was about 20 min delay for inhibition of SCC and the effect was less pronounced. The above effect of SITS was independent of the presence of $Cl^-$ in the bathing medium. The oxygen consumption of the skin tissue was not affected by SITS, but the Na-K-ATPase activity of a subcellular fraction of the skin was significantly inhibited. These results suggest that SITS retards $Na^+$ transport across the frog skin primarily by interfering $Na^+$ entry across the mucosal membrance of the epithelial cell, although an effect on $Na^+$ pump can not be ruled out completely.

• Journal of Physiology & Pathology in Korean Medicine
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• v.16 no.1
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• pp.72-77
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• 2002

The present study was examined the effects of Bojungchiseup-tang water extract on the renal expression of renal function regulatory proteins including aquaporin 2 (AQP 2), aquaporin 3 (AQP 3), Na, K-ATPase α1 subunit, endothelial nitric oxide synthase (ecNOS), and inducible nitric oxide synthase (iNOS) in rats. The renal expression of AQP 3 was attenuated in rats administered with Bojungchiseup-tang water extract without altered expression of AQP 2, while ecNOS was up-regualted. Oral administration of Bojungchiseup-tang water extract (40 ㎕/100 g) also attenuated the renal expression of Na, K-ATPase α1-subunit and iNOS protein. These results suggest that the diuretic and natriuretic effects of Bojungchiseup-tang maybe causely related with a decreased expression of AQP 3 and increased expression of ecNOS.

• Journal of Acupuncture Research
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• v.18 no.2
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• pp.150-160
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• 2001

Objectives ; This study was undertaken to determine whether Carthami-Flos aquacapuncture (CFA) exerts protective effect against oxidant-induced inhibition of $Na^+-K^+$-ATPase activity in cerebral synaptosomes. Methods and Results ; The enzyme activity was dependent on incubation time and enzyme protein concentrations. An oxidant t-butylhydroperoxide (tBHP) at 1 mM concentration caused a significant inhibition of $Na^+-K^+$-ATPase activity, which was prevented by addition of 0.01% CFA. tBHP inhibition and CFA protection were independent on incubation time or enzyme protein concentrations. The enzyme activity was increased by ATP in a dose dependent manner. Effects of tBHP and CFA were not affected by ATP cocentrations. tBHP (1 mM) produced a significant increase in lipid peroxidation in cerebral synaptosomes, which was prevented by 0.01% CFA. CFA decreased oxygen free radicals generated induced by the phorbol-ester in a dose-dependent manner in human neutrophil. Conclusions ; These results suggest that CFA exerts protective effect against tBHP-induced inhibition of $Na^+-K^+$-ATPase activity, which is due to by an antioxidant action resulting from a direct scavenging effect of oxygen free radicals in the cerebral synaptosomes.

• The Korean Journal of Physiology
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• v.30 no.2
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• pp.197-208
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• 1996

Endosomes lower their internal pH by an ATP-driven proton pump, which is critical to dissociation of many receptor-ligand complexes, the first step in the intracellular sorting of internalized receptors and ligands. Endosomes are known to exhibit n great range of pH values that can vary between 5.0 and 7.0 within a single cell although the factors that regulate endosomal pH remain uncertain. To evaluate the morphological and topological differences of endosomes in the different stages, confocal microscopy was used. The early endosomes labeled with fluorescein isothiocyanate-dextran for 10 min at $37^{\circ}C$ were identifiable at the peripheral and tubule-vesicular endosome compartment. In contrast, the late endosomes formed by 10 min pulse and 20 min trace were located deeper in the cytoplasm and showed more vesicular features than early endosomes. For the purpose of determining whether ATP-dependent acidification was heterogeneous and whether the differences in acidification were attributed to differences in the activity of $Na^{+}-K^{+}$-ATPase and/or $Cl^{-}$ channel, endocytic compartments were fractionated into subpopulation using percoll gradient and measured ATP-dependent acidification. While all fractions exhibited ATP-dependent acidification activity, both the initial rate of acidification and extent of proton translocation were lower in early endosomes and gradually increased in late endosomes. Phosphorylation by PKA and ATP enhanced ATP-dependent acidification in both early and late endosomes, hut there was no difference in the degree of enhancement by phosphorylation between two subpopulations. When ATP-dependent acidification was determined in the presence or absence of vanadate ($Na_{3}VO_{4}$) or ouabain, only early endosomes exhibited the vanadate or ouabain dependent stimulation of acidification activity, suggesting the inhibition of $Na^{+}-K^{+}$-ATPase. Therefore, it seems probable that the inhibition of early endosome acidification by $Na^{+}-K^{+}$-ATPase observed in vitro at least in part plays a physiological role in controlling the acidification of early endosomes in vivo.

• Microbiology and Biotechnology Letters
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• v.33 no.4
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• pp.255-259
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• 2005

IgE-dependent histamine-releasing factor (HRF) is found extracellularly to regulate the degranulation process of histamine in mast cells and basophils and known to play a predominant role in the pathogenesis of chronic allergic disease. HRF has been also identified in the intracellular region of the cell. Previously, we reported that HRF interacts with the 3rd cytoplasmic domain of the alpha subunit of Na,K-ATPase. To understand the molecular mechanism of the regulation of Na, K-ATPase activity by HRF, we investigated the interaction between HRF and TPI since TPI was obtained as HRF-interacting protein in HeLa cDNA library, using yeast two hybrid screening. Domain mapping study of the interaction between HRF and TPI revealed that the C-terminal region of the residue 156-249 of TPI is involved in the interaction with HRF. The interaction between HRF and TPI was confirmed by immunoprecipitation from HeLa cell extracts. Our results suggest that TPI is a HRF-binding protein and the interaction between HRF and TPI nay thus affect Na, K-ATPase activity.