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Wyszukujesz frazę "ouabain" wg kryterium: Temat


Wyświetlanie 1-2 z 2
Tytuł:
The involvement of Na+/K+-ATPase in the development of platelet procoagulant response
Autorzy:
Tomasiak, Marian
Stelmach, Halina
Rusak, Tomasz
Ciborowski, Michał
Radziwon, Piotr
Powiązania:
https://bibliotekanauki.pl/articles/1041052.pdf
Data publikacji:
2007
Wydawca:
Polskie Towarzystwo Biochemiczne
Tematy:
cardiac glycosides
ouabain
Na+/K+-ATPase
atrial fibrillation
platelets
procoagulant activity
Opis:
In circulation, platelets may come into contact with both exogenous (cardiac glycoside treatment) and endogenously produced inhibitors of Na+/K+-ATPase. We examined whether blocking of platelet Na+/K+-ATPase by ouabain results in generation of procoagulant activity. It was shown that an in vitro treatment of platelets with ouabain (20-200 µM for 20 to 60 min) is associated with an intracellular accumulation of sodium ([Na+]i), generation of a weak calcium signal, and expression of procoagulant activity. The ouabain-induced procoagulant response was dose- and time-related, less pronounced than that evoked by collagen and similar to that produced by gramicidin, not affected by EDTA or aspirin, and strongly reduced in the absence of extracellular Na+ or by hyperosmolality. Flow cytometry studies revealed that ouabain treatment results in a unimodal left shift in the forward and side scatter of the entire platelet population indicating morphological changes of the plasma membrane. The shift was dose related, weaker than that evoked by collagen and similar to that produced by gramicidin. Ouabain-treated platelets express phosphatidylserine (PS). The ouabain-evoked PS expression was dose- and time-dependent, weaker than that produced by collagen and similar to that evoked by gramicidin. Electronic cell sizing measurements showed a dose-dependent increase in mean platelet volume upon treatment with ouabain. Hypoosmotically-evoked platelet swelling resulted in the appearance of procoagulant activity. Thromboelastography measurements indicate that, in whole blood, nanomolar (50-1000 nM, 15 min) concentrations of ouabain significantly accelerate the rate of clot formation initiated by contact and high extracellular concentration of calcium. We conclude that inefficiently operating platelet Na+/K+-ATPase results in a rise in [Na+]i. An increase in [Na+]i and the swelling associated with it may produce PS exposure and a rise in membrane curvature leading to the generation of a procoagulant activity.
Źródło:
Acta Biochimica Polonica; 2007, 54, 3; 625-639
0001-527X
Pojawia się w:
Acta Biochimica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Spectrophotometric method for the determination of renal ouabain-sensitive H+,K+ -ATPase activity.
Autorzy:
Bełtowski, Jerzy
Wójcicka, Grażyna
Powiązania:
https://bibliotekanauki.pl/articles/1043791.pdf
Data publikacji:
2002
Wydawca:
Polskie Towarzystwo Biochemiczne
Tematy:
leptin
kidney
H+,K+-ATPase
ouabain
Sch 28080
Na+,K+-ATPase
Opis:
The aim of this work was to develop a method for renal H+,K+-ATPase measurement based on the previously used Na+,K+-ATPase assay (Bełtowski et al.: J Physiol Pharmacol.; 1998, 49: 625-37). ATPase activity was assessed by measuring the amount of inorganic phosphate liberated from ATP by isolated microsomal fraction. Both ouabain-sensitive and ouabain-resistant K+-stimulated and Na+-independent ATPase activity was detected in the renal cortex and medulla. These activities were blocked by 0.2 mM imidazolpyridine derivative, Sch 28080. The method for ouabain- sensitive H+,K+-ATPase assay is characterized by good reproducibility, linearity and recovery. In contrast, the assay for ouabain-resistant H+,K+-ATPase was unsatisfactory, probably due to low activity of this enzyme. Ouabain-sensitive H+,K+-ATPase was stimulated by K+ with Km of 0.26 ± 0.04 mM and 0.69 ± 0.11 mM in cortex and medulla, respectively, and was inhibited by ouabain (Ki of 2.9 ± 0.3 μM in the renal cortex and 1.9 ± 0.4 μM in the renal medulla) and by Sch 28080 (Ki of 1.8 ± 0.5 μM and 2.5 ± 0.9 μM in cortex and medulla, respectively). We found that ouabain-sensitive H+,K+-ATPase accounted for about 12% of total ouabain-sensitive activity in the Na+,K+-ATPase assay. Therefore, we suggest to use Sch 28080 during Na+,K+-ATPase measurement to block H+,K+-ATPase and improve the assay specificity. Leptin administered intraperitoneally (1 mg/kg) decreased renal medullary Na+,K+-ATPase activity by 32.1% at 1 h after injection but had no effect on H+,K+-ATPase activity suggesting that the two renal ouabain-sensitive ATPases are separately regulated.
Źródło:
Acta Biochimica Polonica; 2002, 49, 2; 515-527
0001-527X
Pojawia się w:
Acta Biochimica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-2 z 2

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