3 edition of Intracellular potassium and sodium ionic activities of cardiac muscles found in the catalog.
Intracellular potassium and sodium ionic activities of cardiac muscles
Written in English
|Statement||by Shey-shing Sheu.|
|LC Classifications||Microfilm 80050 (Q)|
|The Physical Object|
|Pagination||vi, 103 leaves|
|Number of Pages||103|
|LC Control Number||82187253|
Cardiac Na +-K +-ATPase (NKA) regulates intracellular Na +, which in turn affects intracellular Ca 2+ and contractility via the Na + /Ca 2+ exchanger. Extracellular K + concentration ([K +]) is a central regulator of NKA olemman (PLM) has recently been recognized as a critical regulator of NKA in the heart. PLM reduces the intracellular Na + affinity of NKA, an effect . [Show full abstract] that there must be active sodium excretion to control intracellular sodium levels in skeletal muscle. () showed that the sodium and potassium fluxes across red blood cell.
In a cardiac cell, the concentration of K + is high inside the cell and low outside. Therefore, there is a chemical gradient for K + to diffuse out of the cell. The opposite situation is found for Na + and Ca ++ where their chemical gradients (high outside, low inside concentrations) favor an inward diffusion. Potassium . Almost all (98%) of the body’s potassium is in intracellular fluid (predominately in muscle, liver and erythrocytes) with the remainder circulating in the serum. This large difference in concentration between intra- and extracellular fluid is maintained by enzymes (Na-K-ATPase) that actively pump potassium into the cell and sodium out, to.
Increase in Intracellular Sodium Ion Activity during Stimulation in Mammalian Cardiac Muscle Charles J. Cohen, Harry A. Fozzard, and Shey-Shing Sheu From the Departments of Medicine (Cardiology) and Pharmacological and Physiological Sciences, The University of Chicago, Chicago, Illinois SUMMARY. Sodium, potassium together influence heart health Published: September, When it comes to salt and food, the sodium in table salt gets most of the attention for its role in boosting blood pressure and contributing to cardiovascular disease.
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Activities of potassium and sodium ions in rabbit heart muscle. J Gen Physiol. Jun; 65 (6)– [PMC free article] Houser SR, Freeman AR.
A simple method for volumetric measurements in isolated cardiac muscle. Am J Physiol. Mar; (3):H–H Ladle RO, Walker JL. Intracellular chloride activity in frog by: 5. Similar results were obtained at 35 +/- 1 degree C.
gammaK was substantially lower than the activity coefficient () of extracellular fluid (Tyrode's solution), which might be expected on the basis of a different intracellular ionic strength. gammaNa was much lower than that of extracellular fluid, and suggest that much of the Na was Cited by: Activities of potassium and sodium ions in rabbit heart muscle.
C O Lee. C O LeeCited by: Na⁺/K⁺-ATPase (sodium–potassium adenosine triphosphatase, also known as the Na⁺/K⁺ pump or sodium–potassium pump) is an enzyme (an electrogenic transmembrane ATPase) found in the membrane of all animal cells. It performs several functions in cell physiology.
The Na + /K +-ATPase enzyme is active (i.e. it uses energy from ATP).For every ATP molecule that the pump uses, three sodium BRENDA: BRENDA entry. Abstract. When liquid ion exchanger, ion selective microelectrodes, with tip diameters of less than were developed (Walker, ), it seemed reasonable to use them to measure intracellular potassium and chloride activities, a i (K) and a i (Cl), in sheep cardiac Purkinje fibers.
This preparation was chosen for two reasons, it has been a popular preparation for cardiac electrophysiologists Cited by: 4. CiteSeerX - Document Details (Isaac Councill, Lee Giles, Pradeep Teregowda): ABSTRACT The intracellular sodium concentration reported for young, embryonic chick hearts is extremely high and decreases progressively throughout the embryonic period, reaching a value of 43 mM immediately before hatching.
This observation suggested that the ionic basis for excitation in embryonic chick heart may. Magnesium and potassium are the 2 major intracellular cations.
The intracellular concentrations of these 2 ions appear to be closely correlated, but the existence of a relationship between the plasma concentrations of these ions has been controversial. A major function of potassium is to maintain the excitability of nerve and muscle tissue. Along with sodium and calcium, the role of potassium in muscle contraction is an important one.
Considered to be one of the many important minerals required by the body in order to function properly, potassium is also classified as an electrolyte because it carries an electrical charge.
Langer, G. & Serena, S. () Effects of strophanthidin upon contraction and ionic exchange in rabbit ventricular myocardium: relation to control of active state.
Journal of Molecular and Cellular Cardiology, 1, Lee, C. & Fozzard, H. () Activities of potassium and sodium ions in rabbit heart muscle. Cardiac Muscle: The Regulation of Excitation and Contraction is a chapter text that covers the research studies on characterizing the ionic and molecular mechanisms that regulate excitation and contraction of cardiac muscle.
This book describes first the ionic currents underlying diastolic depolarization and pacing of the heart. Potassium is largely—approximately 98%—found extracellularly. The proper concentration is maintained at the cellular level by the Na + /K +-ATPase (sodium/potassium–adenosine triphosphatase) pump, located on cell membranes, which removes 3 Na + ions from the cell in exchange for 2 K + ions.
This is especially vital in nerve cells for maintaining the proper electrochemical membrane potential. Similar to skeletal muscle, the resting membrane potential (voltage when the cell is not electrically excited) of ventricular cells, is around millivolts (mV; 1 mV = V) i.e.
the inside of the membrane is more negative than the main ions found outside the cell at rest are sodium (Na +), and chloride (Cl −), whereas inside the cell it is mainly potassium (K +). Activities of Potassium and Sodium Ions in Rabbit Heart Muscle a different intracellular ionic strength.
3'N, was much lower than that of extra- the ionic activities in the muscle cells under different K concentrations of the bathing solution were measured with the cation-selective glass microelectrodes.
Potassium, Sodium, and Cardiovascular Disease Burden. Increasing potassium intake can reduce the risk of cardiovascular diseases, such as heart disease and stroke, by lowering blood pressure. 8,9; Consuming high amounts of sodium and low amounts of potassium can increase a person’s risk for heart disease and stroke.
5,10,11, The intracellular concentration of potassium is about 30 times higher than the extracellular concentration, and this difference forms a transmembrane electrochemical gradient that is maintained via the sodium-potassium (Na+/K+) ATPase transporter.
In addition to maintaining cellular tonicity, this gradient is required for proper nerve. Intracellular calcium concentrations in both cardiac and vascular smooth muscle cells range from to M.
Extracellular concentration of calcium is about 2 × M (2 mM). Therefore, there is a chemical gradient for calcium to diffuse into the cell. Abstract. Intracellular [Na +] ([Na +] i) is regulated in cardiac myocytes by a balance of Na + influx and efflux mechanisms.
In the normal cell there is a large steady state electrochemical gradient favoring Na + influx. This potential energy is used by numerous transport mechanisms, including Na + channels and transporters which couple Na + influx to either co- or counter-transport of other.
The effects of membrane potential, extracellular potassium, and tetrodotoxin on the intracellular sodium ion activity of sheep cardiac muscle. Circulation Research54 (6), DOI: /RES M G Lado, S S Sheu, H A Fozzard. For every three sodium ions pumped out of the cell, two potassium ions are pumped in.
This transport produces both a chemical and an electrical gradient across the cell membrane. The electrical gradient is essential for maintaining the resting potential of cells and for the excitable activity of muscle and nerve tissue. The sodium gradient is.
Kernan R.P., MacDermott M., (). Intracellular potassium concentrations and extracellular spaces in rat skeletal muscles immersed in normal, hypotonic and high-K modified Krebs fluid, determined by potassium-selective micro-electrodes.
Physiol. (Lond) P. Google Scholar. In the discussion of membrane potentials in Chapter 5, it was pointed out that potassium ions have a marked effect on membrane potentials, and in Chapter 6 it was noted that calcium ions play an especially important role in activating the muscle contractile process.
Therefore, it is to be expected that the concentration of each of these two ions in the extracellular fluids should also have.[Potassium and sodium content in various parts of the cardiac and skeletal muscles in horses] Intracellular ionic activity measurements in nerve and muscle.
Walker JL, Brown HM. Physiol Rev, 57(4), 01 Oct The movement of _____ into the cardiac muscle cell depolarizes the cardiac muscle cell. 33) A) calcium B) sodium C) potassium D) sodium and calcium E) potassium, sodium and calcium.
Increasing the intracellular potassium decreases the resting potential.