Potassium-induced changes in the electromechanical and ATPase activity of guinea pig heart. 1976

K Prasad

The effects of various concentrations (0, 0.5, 1, 2, 4, and 8 mM) of potassium chloride on the simultaneously recorded action potential and contractility; and Mg++-dependent, Na++-K+-stimulated membrane ATPase of guinea pig's heart were studied. In KCl-free solution, the inhibition of the Na+-K+-ATPase was associated both with a shortening of the duration of action potential and an increase in the contractility. There was a decrease in the overshoot of action potential and an increase in the resting potential. Potassium chloride produced a concentration dependent lengthening of the action potential duration; decrease in the contraction and resting potential; and an increase in the overshoot of action potential and Na+-K+-ATPase activity. The changes in the action potential and contraction were associated with the changes in the Na+-K-ATPase activity. The changes in the ATPase activity preceded the changes in the action potential and contractility. The involvement of ATPase in the genesis of the resting potential; overshoot and duration of action potential; and contraction has been discussed.

UI MeSH Term Description Entries
D008274 Magnesium A metallic element that has the atomic symbol Mg, atomic number 12, and atomic weight 24.31. It is important for the activity of many enzymes, especially those involved in OXIDATIVE PHOSPHORYLATION.
D009200 Myocardial Contraction Contractile activity of the MYOCARDIUM. Heart Contractility,Inotropism, Cardiac,Cardiac Inotropism,Cardiac Inotropisms,Contractilities, Heart,Contractility, Heart,Contraction, Myocardial,Contractions, Myocardial,Heart Contractilities,Inotropisms, Cardiac,Myocardial Contractions
D009206 Myocardium The muscle tissue of the HEART. It is composed of striated, involuntary muscle cells (MYOCYTES, CARDIAC) connected to form the contractile pump to generate blood flow. Muscle, Cardiac,Muscle, Heart,Cardiac Muscle,Myocardia,Cardiac Muscles,Heart Muscle,Heart Muscles,Muscles, Cardiac,Muscles, Heart
D010210 Papillary Muscles Conical muscular projections from the walls of the cardiac ventricles, attached to the cusps of the atrioventricular valves by the chordae tendineae. Muscle, Papillary,Muscles, Papillary,Papillary Muscle
D011188 Potassium An element in the alkali group of metals with an atomic symbol K, atomic number 19, and atomic weight 39.10. It is the chief cation in the intracellular fluid of muscle and other cells. Potassium ion is a strong electrolyte that plays a significant role in the regulation of fluid volume and maintenance of the WATER-ELECTROLYTE BALANCE.
D011189 Potassium Chloride A white crystal or crystalline powder used in BUFFERS; FERTILIZERS; and EXPLOSIVES. It can be used to replenish ELECTROLYTES and restore WATER-ELECTROLYTE BALANCE in treating HYPOKALEMIA. Slow-K,Chloride, Potassium
D004558 Electric Stimulation Use of electric potential or currents to elicit biological responses. Stimulation, Electric,Electrical Stimulation,Electric Stimulations,Electrical Stimulations,Stimulation, Electrical,Stimulations, Electric,Stimulations, Electrical
D004594 Electrophysiology The study of the generation and behavior of electrical charges in living organisms particularly the nervous system and the effects of electricity on living organisms.
D006168 Guinea Pigs A common name used for the genus Cavia. The most common species is Cavia porcellus which is the domesticated guinea pig used for pets and biomedical research. Cavia,Cavia porcellus,Guinea Pig,Pig, Guinea,Pigs, Guinea
D006321 Heart The hollow, muscular organ that maintains the circulation of the blood. Hearts
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