(Na+-K+)-ATPase Activity and Ouabain-Binding Sites in the Cerebral Cortex of Young and Aged Fischer-344 Rats

Gerontology ◽  
1983 ◽  
Vol 29 (4) ◽  
pp. 242-247 ◽  
Author(s):  
Joseph C. LaManna ◽  
Gregory Doull ◽  
Kimberly McCracken ◽  
Sami I. Harik
1993 ◽  
Vol 265 (6) ◽  
pp. H2086-H2093 ◽  
Author(s):  
T. H. Fan ◽  
R. P. Frantz ◽  
H. Elam ◽  
S. Sakamoto ◽  
N. Imai ◽  
...  

To study the changes in myocardial digitalis binding sites in heart failure, we measured myocardial ouabain binding sites, Na-K-adenosinetriphosphatase (ATPase) activity, and ventricular muscle mechanical responses to acetylstrophanthidin in dogs with right-heart failure (RHF) produced by tricuspid avulsion and pulmonary artery constriction. Sham-operated dogs were studied as the control. RHF produced a significant decrease in ouabain binding sites in the right and left ventricular myocardium, which was accompanied by a proportional decrease in Na-K-ATPase activity. However, RHF and sham-operated dogs did not differ in systemic hemodynamic or right ventricular trabeculate muscle isometric contractile responses to acetylstrophanthidin. To determine whether chronic beta-adrenergic stimulation contributed to the development of Na-K-ATPase downregulation, we administered nadolol (40 mg/day) to a separate group of dogs during an early stage of RHF development. Nadolol effectively prevented the reduction of myocardial ouabain binding sites that occurred in RHF. Thus we conclude that myocardial ouabain binding sites and Na-K-ATPase activity are reduced in dogs with experimental heart failure and that these changes probably occur as a result of the attendant heightened sympathetic activity.


1990 ◽  
Vol 259 (5) ◽  
pp. H1330-H1336 ◽  
Author(s):  
R. C. Kukreja ◽  
A. B. Weaver ◽  
M. L. Hess

One of the targets of free radicals and neutrophil-derived oxidants that is known to be generated during ischemic-reperfusion injury of the myocardium is the sarcolemma. We therefore examined the susceptibility of sarcolemmal Na(+)-K(+)-ATPase and ouabain binding sites to O2-., H2O2,.OH, HOCl, NH2Cl, and stimulated neutrophils. O2-. generated from xanthine oxidase action on xanthine had no significant effect on Na(+)-K(+)-ATPase activity. The inhibition of Na(+)-K(+)-ATPase activity and ouabain binding by H2O2 was dependent on concentration and the time of incubation. H2O2 (10 mM) inhibited 80% of Na(+)-K(+)-ATPase activity at 90 min..OH generated by Fenton's reagent (200 microM Fe2+ + 5 mM H2O2) significantly decreased maximum binding of ouabain (43.06 +/- 1.45 to 31.96 +/- 2.37 pmol/mg) and was significantly protected by 5 mM mannitol (P less than 0.05). The dissociation constant of ouabain binding was unaffected by Fenton's reagent or H2O2. In contrast, lower concentrations of HOCl, NH2Cl, or PMA-stimulated human neutrophils (4 X 10(6) cells/ml) had significant inhibitory effects on Na(+)-K(+)-ATPase activity. We conclude that O-2. per se is not damaging to sarcolemmal Na(+)-K(+)-ATPase activity. The formation of H2O2 and the more destructive .OH or HOCl and NH2Cl disrupt sarcolemmal function by inhibiting Na(+)-K(+)-ATPase activity and destroying ouabain binding sites.


1985 ◽  
Vol 69 (4) ◽  
pp. 441-447 ◽  
Author(s):  
Alan C. Swann

1. These experiments examined the effects of a high NaCl diet on (Na+, K+)-ATPase in kidney, heart and cerebral cortex, on the level of circulating inhibitor of (Na+, K+)-ATPase in plasma, and on stimulation of (Na+, K+)-ATPase by treatment with dextro (d)-amphetamine. 2. High salt diet increased indices of (Na+, K+)-ATPase activity (K+-activated p-nitrophenylphosphatase activity and ouabain binding) in kidney medulla, prevented stimulation by amphetamine in cerebral cortex and reduced amphetamine stimulation in heart. 3. High NaCl feeding increased the plasma level of circulating inhibitor of (Na+, K+)-ATPase. 4. Amphetamine alone had no effect on inhibitor level but amphetamine administration reduced the increase in inhibitor with high NaCl feeding.


2005 ◽  
Vol 289 (1) ◽  
pp. R266-R274 ◽  
Author(s):  
A. C. Petersen ◽  
K. T. Murphy ◽  
R. J. Snow ◽  
J. A. Leppik ◽  
R. J. Aughey ◽  
...  

We investigated whether depressed muscle Na+-K+-ATPase activity with exercise reflected a loss of Na+-K+-ATPase units, the time course of its recovery postexercise, and whether this depressed activity was related to increased Na+-K+-ATPase isoform gene expression. Fifteen subjects performed fatiguing, knee extensor exercise at ∼40% maximal work output per contraction. A vastus lateralis muscle biopsy was taken at rest, fatigue, 3 h, and 24 h postexercise and analyzed for maximal Na+-K+-ATPase activity via 3- O-methylfluorescein phosphatase (3- O-MFPase) activity, Na+-K+-ATPase content via [3H]ouabain binding sites, and Na+-K+-ATPase α1-, α2-, α3-, β1-, β2- and β3-isoform mRNA expression by real-time RT-PCR. Exercise [352 (SD 267) s] did not affect [3H]ouabain binding sites but decreased 3- O-MFPase activity by 10.7 (SD 8)% ( P < 0.05), which had recovered by 3 h postexercise, without further change at 24 h. Exercise elevated α1-isoform mRNA by 1.5-fold at fatigue ( P < 0.05). This increase was inversely correlated with the percent change in 3- O-MFPase activity from rest to fatigue (%Δ3- O-MFPaserest-fatigue) ( r = −0.60, P < 0.05). The average postexercise (fatigue, 3 h, 24 h) α1-isoform mRNA was increased 1.4-fold ( P < 0.05) and approached a significant inverse correlation with %Δ3- O-MFPaserest-fatigue ( r = −0.56, P = 0.08). Exercise elevated α2-isoform mRNA at fatigue 2.5-fold ( P < 0.05), which was inversely correlated with %Δ3- O-MFPaserest-fatigue ( r = −0.60, P = 0.05). The average postexercise α2-isoform mRNA was increased 2.2-fold ( P < 0.05) and was inversely correlated with the %Δ3- O-MFPaserest-fatigue ( r = −0.68, P < 0.05). Nonsignificant correlations were found between %Δ3- O-MFPaserest-fatigue and other isoforms. Thus acute exercise transiently decreased Na+-K+-ATPase activity, which was correlated with increased Na+-K+-ATPase gene expression. This suggests a possible signal-transduction role for depressed muscle Na+-K+-ATPase activity with exercise.


1996 ◽  
Vol 127 (1) ◽  
pp. 59-64 ◽  
Author(s):  
Wen-Jone Chen ◽  
Shoei-Yn Lin-Shiau ◽  
Huei-Chen Huang ◽  
Yuan-Teh Lee

1998 ◽  
Vol 247 (2-3) ◽  
pp. 79-82 ◽  
Author(s):  
Youngbuhm Huh ◽  
Wonkyu Lee ◽  
Jungsik Cho ◽  
Heekyung Ahn

Metabolism ◽  
1991 ◽  
Vol 40 (8) ◽  
pp. 819-824 ◽  
Author(s):  
Faith B. Davis ◽  
Mark R. Deziel ◽  
Judith B. Van Liew ◽  
Paul J. Davis ◽  
Lee L. Bernardis ◽  
...  

1999 ◽  
Vol 87 (3) ◽  
pp. 1132-1140 ◽  
Author(s):  
Xiwu Sun ◽  
Murali Nagarajan ◽  
Philip W. Beesley ◽  
Yuk-Chow Ng

Skeletal muscle expresses multiple isoforms of the Na+-K+-ATPase. Their expression has been shown to be differentially regulated under pathophysiological conditions. In addition, previous studies suggest possible age-dependent alterations in Na+-K+pump function. The present study tests the hypothesis that advancing age is associated with altered Na+-K+-ATPase enzyme activity and isoform-specific changes in expression of the enzyme subunits. Red and white gastrocnemius (Gast) as well as soleus muscles of male Fischer 344/Brown Norway (F-344/BN) rats at 6, 18, and 30 mo of age were examined. Na+-K+-ATPase activity, measured by K+-stimulated 3- O-methylfluorescein phosphatase activity, increased by ∼50% in a mixed Gast homogenate from 30-mo-old compared with 6- and 18-mo-old rats. Advancing age was associated with markedly increased α1- and β1-subunit, and decreased α2- and β2-subunit in red and white Gast. In soleus, there were similar changes in expression of α1- and α2-subunits, but levels of β1-subunit were unchanged. Functional Na+-K+-ATPase units, measured by [3H]ouabain binding, undergo muscle-type specific changes. In red Gast, high-affinity ouabain-binding sites, which are a measure of α2-isozyme, increased in 30-mo-old rats despite decreased levels of α2-subunit. In white Gast, by contrast, decreased levels of α2-subunit were accompanied by decreased high-affinity ouabain-binding sites. Finally, patterns of expression of the four myosin heavy chain (MHC) isoforms (type I, IIA, IIX, and IIB) in these muscles were similar in the three age groups examined. We conclude that, in the skeletal muscles of F-344/BN rats, advancing age is associated with muscle type-specific alterations in Na+-K+-ATPase activity and patterns of expression of α- and β-subunit isoforms. These changes apparently occurred without obvious shift in muscle fiber types, since expression of MHC isoforms remained unchanged. Some of the alterations occurred between middle-age (18 mo) and senescence (30 mo), and, therefore, may be attributed to aging of skeletal muscle.


Metabolism ◽  
1990 ◽  
Vol 39 (9) ◽  
pp. 952-957 ◽  
Author(s):  
Mano Arumanayagam ◽  
Dorothy MacDonald ◽  
C.S. Cockram ◽  
R. Swaminathan

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