scholarly journals Inhibition of the sodium pump in guinea-pig ventricular muscle by dihydro-ouabain: effects of external potassium and sodium.

1983 ◽  
Vol 339 (1) ◽  
pp. 643-662 ◽  
Author(s):  
J Daut
Keyword(s):  
Guinea Pig ◽  
Sodium Pump ◽  
Ventricular Muscle ◽  
External Potassium

Sodium-Potassium Movement and the Regulation of Cardiac Muscle Activity

1982 ◽  
Vol 37 (7-8) ◽  
pp. 679-681
Author(s):  
Jürgen Daut ◽  
Reinhardt Rüdel
Keyword(s):  
Guinea Pig ◽  
Cardiac Muscle ◽  
Muscle Activity ◽  
Cardiac Glycoside ◽  
Sodium Pump ◽  
Ventricular Muscle ◽  
Sodium Potassium ◽  
Sodium Activity ◽  
Electrogenic Sodium Pump ◽  
Fast Acting

Abstract The changes in intracellular sodium activity and contractility produced by short-lasting application of a fast-acting cardiac glycoside were measured in guinea-pig ventricular muscle. It was found that under certain conditions the change in twitch tension paralleled the change in sodium activity. It is suggested that the electrogenic sodium pump may be involved in the regulation of both the mechanical and the electrical activity of cardiac muscle.

Action of acetylcholine on the longitudinal muscle of guinea-pig ileum: the role of an electrogenic sodium pump

1973 ◽  
Vol 265 (867) ◽  
pp. 107-114 ◽  
Keyword(s):  
Membrane Potential ◽  
Guinea Pig ◽  
Sodium Pump ◽  
Longitudinal Muscle ◽  
Membrane Resistance ◽  
Free Solution ◽  
Electrogenic Sodium Pump ◽  
External Potassium ◽  
Sodium And Potassium

Intracellular recordings of membrane potential were made from the longitudinal muscle of guinea-pig terminal ileum. It was observed that ouabain or potassium-free solution depolarized the membrane. Upon readmitting potassium to potassium-free solution, the membrane potential rapidly increased. This response was blocked by ouabain and was potentiated in chloride-deficient solution, suggesting that it was due to the activity of an electrogenic sodium pump. When acetylcholine was applied, and then washed from the tissue, there followed a period of increased negativity of the membrane potential, an after-hyperpolarization. This did not occur when responses to acetylcholine were obtained in the presence of ouabain, in potassium-free solution, or in sodium-deficient solution, but the after-hyperpolarization was increased in size in chloride-deficient solution. During a 2 min application of carbachol, the membrane potential fell more rapidly in the presence of ouabain (10 -5 mol/1); this could be explained if sodium pump activity is important in retarding the decline of the sodium and potassium gradients that occurs at this time. It was concluded that the application of acetylcholine or carbachol to ileal muscle increases internal sodium and probably external potassium concentrations. These increases stimulate the activity of the electrogenic sodium pump so that, when the membrane resistance recovers, there is an increased electrogenic contribution to the membrane potential. This produces the after-hyperpolarization which is a feature of the response to acetylcholine.

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