Transient inhibition of the muscarinic actions of carbachol during reactivation of the electrogenic sodium pump in guinea pig taenia caeci smooth muscle

1985 ◽  
Vol 63 (6) ◽  
pp. 663-668
Author(s):  
Tamás L. Török ◽  
Sylvester E. Vizi ◽  
Kálmán Magyar
Keyword(s):  
Smooth Muscle ◽  
Guinea Pig ◽  
Muscarinic Receptor ◽  
Sodium Pump ◽  
External Medium ◽  
Free Solution ◽  
Electrogenic Sodium Pump

In guinea pig taenia caeci smooth muscle the muscarinic receptor stimulant carbachol evoked depolarization and contraction, which was followed by hyperpolarization and relaxation on its removal. Both the hyperpolarization and relaxation were inhibited by removal of K+ from the external medium. During Na+-pump blockade (K+-free solution) the depolarizing and contracting actions of carbachol decreased. When the Na+ pump was switched on again by readmission of 5.9 mmol/L K+ to K+-depleted and Na+-enriched preparations, electrogenic hyperpolarization and relaxation developed. During this period carbachol failed to produce depolarization and contraction.

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.

Monovalent Ion Specificity of the Electrogenic Sodium Pump in Vascular Smooth Muscle

1981 ◽  
Vol 166 (3) ◽  
pp. 457-461 ◽  
Author(s):  
R. C. Webb ◽  
W. E. Lockette ◽  
P. M. Vanhoutte ◽  
D. F. Bohr
Keyword(s):  
Smooth Muscle ◽  
Vascular Smooth Muscle ◽  
Sodium Pump ◽  
Ion Specificity ◽  
Electrogenic Sodium Pump ◽  
Monovalent Ion

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.

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