» Articles » PMID: 2580969

Relation of Sodium Pump Inhibition to Positive Inotropy at Low Concentrations of Ouabain in Rat Heart Muscle

Overview
Journal J Physiol
Specialty Physiology
Date 1985 Mar 1
PMID 2580969
Citations 19
Authors
Affiliations
Soon will be listed here.
Abstract

Low concentrations of ouabain which produce a positive inotropic effect on rat ventricular muscle do not inhibit the isolated Na+-K+-ATPase enzyme from this tissue, suggesting that these low-concentration inotropic effects are not related to sodium pump inhibition (Erdmann, Philipp & Scholz, 1980; Adams, Schwartz, Grupp, Grupp, Lee, Wallick, Powell, Twist & Gathiram, 1982). We tested this hypothesis by continuously measuring intracellular Na+ activity with Na+-selective micro-electrodes and, separately, twitch tension of rat ventricular muscle during exposure to and wash-out of ouabain. Intracellular Na+ activity (aiNa) and transmembrane potential of quiescent muscle cells averaged 8.5 +/- 2.6 mM (mean +/- S.D., n = 27) and -79.2 +/- 2.4 mV (n = 34) respectively. Low concentrations of ouabain (0.1, 0.5 and 1.0 microM) produced concentration-dependent increases in both aiNa and twitch tension. At lower concentrations of ouabain (0.01 and 0.05 microM), no detectable changes in aiNa and twitch tension were observed. The data strongly indicate that in rat ventricular muscle sodium pump inhibition is present at low concentrations of ouabain which produce positive inotropy. This is consistent with previous results in canine and sheep cardiac Purkinje fibres.

Citing Articles

Cardiac Glycosides as Autophagy Modulators.

Skubnik J, Pavlickova V, Psotova J, Rimpelova S Cells. 2021; 10(12).

PMID: 34943848 PMC: 8699753. DOI: 10.3390/cells10123341.


Sodium Transporters in Human Health and Disease.

Gagnon K, Delpire E Front Physiol. 2021; 11:588664.

PMID: 33716756 PMC: 7947867. DOI: 10.3389/fphys.2020.588664.


Is there a causal link between intracellular Na elevation and metabolic remodelling in cardiac hypertrophy?.

Aksentijevic D, OBrien B, Eykyn T, Shattock M Biochem Soc Trans. 2018; 46(4):817-827.

PMID: 29970448 PMC: 6103460. DOI: 10.1042/BST20170508.


Tubacin suppresses proliferation and induces apoptosis of acute lymphoblastic leukemia cells.

Aldana-Masangkay G, Rodriguez-Gonzalez A, Lin T, Ikeda A, Hsieh Y, Kim Y Leuk Lymphoma. 2011; 52(8):1544-55.

PMID: 21699378 PMC: 4113006. DOI: 10.3109/10428194.2011.570821.


Phospholemman: a novel cardiac stress protein.

Cheung J, Zhang X, Song J, Gao E, Rabinowitz J, Chan T Clin Transl Sci. 2010; 3(4):189-96.

PMID: 20718822 PMC: 3013348. DOI: 10.1111/j.1752-8062.2010.00213.x.


References
1.
Adams R, Schwartz A, GRUPP G, GRUPP I, Lee S, Wallick E . High-affinity ouabain binding site and low-dose positive inotropic effect in rat myocardium. Nature. 1982; 296(5853):167-9. DOI: 10.1038/296167a0. View

2.
Matsui H, Schwartz A . Mechanism of cardiac glycoside inhibition of the (Na+-K+)-dependent ATPase from cardiac tissue. Biochim Biophys Acta. 1968; 151(3):655-63. DOI: 10.1016/0005-2744(68)90013-2. View

3.
Sheu S, Fozzard H . Transmembrane Na+ and Ca2+ electrochemical gradients in cardiac muscle and their relationship to force development. J Gen Physiol. 1982; 80(3):325-51. PMC: 2228682. DOI: 10.1085/jgp.80.3.325. View

4.
Watanabe T, Delbridge L, BUSTAMANTE J, McDONALD T . Heterogeneity of the action potential in isolated rat ventricular myocytes and tissue. Circ Res. 1983; 52(3):280-90. DOI: 10.1161/01.res.52.3.280. View

5.
Lechat P, Malloy C, Smith T . Active transport and inotropic state in guinea pig left atrium. Circ Res. 1983; 52(4):411-22. DOI: 10.1161/01.res.52.4.411. View