Abstract
The effect of extracellular magnesium concentration (Mgo) on the upstroke of the action potential was studied in guinea pig ventricular muscle under various K+ concentrations (2.7–19mM). Increased Mgo shifted the steady state inactivation curve of the fast Na channel in the depolarizing direction and this effect was concentration-dependent (0–20mM). Such an effect could explain the Mg-induced increase in maximum rate of rise of the action potential which Späh and Fleckenstein (1979) proposed to be due to a “Mg channel”.
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Arita, M., Kiyosue, T.: Effect of isoproterenol on “residual fast channel dependent slow conduction” produced in guinea pig ventricular muscle. Am. J. Cardiol. 47: 475 (1981)
Beeler, G. W., Reuter, H.: Reconstruction of the action potential of ventricular myocardial fibers. J. Physiol. 268: 177–210 (1977)
Cohen, I., Attwell, D., Strichartz, G.: The dependence of the maximum rate of rise of the action potential upstroke on membrane properties, Proc. R. Soc. Lond. 214: 85–98 (1981)
Frankenhaeuser, B., Hodgkin, A. L.: The action of calcium on the electrical properties of squid axon. J. Physiol. 137: 218–244 (1957)
Hogan, P. M., Spitzer, K. W.: Manganese and electrogenic phenomena in canine Purkinje fibers. Circ. Res. 36: 377–391 (1975)
Schauf, C. L.: The interactions of calcium withMyxicola giant axons and a description in terms of a simple surface charge model. J. Physiol. 248: 613–624 (1975)
Schneider, J. A., Sperelakis, N.: The demonstration of energy dependence of the isoproterenol-induced transcellular calcium current in isolated perfused guinea pig hearts-An explanation for mechanical failure. J. Surg. Res. 16: 389–403 (1974)
Späh, F., Fleckenstein A.: Evidence of a new, preferentially Mg-carring, transport system besides the fast Na and slow Ca channels in the excited myocardial sarcolemma membrane. J. Mol. Cell. Cardiol. 11: 1109–1127 (1979)
Walton, M., Fozzard, H. A.: The relation of\(\dot V_{max}\) to INa,\(\bar G_{Na}\) and h∞ in a model of the cardiac Purkinje fiber. Biophys. J. 25: 407–420 (1979)
Weidmann, S.: Effects of calcium ions and local anaesthetics on electrical properties of Purkinje fibers. J. Physiol. 129: 568–582 (1955)
Windisch, H., Tritthart, H. A.: Calcium ion effects on the rising phase of action potentials obtained from guinea-pig papillary muscle at different potassium concentrations. J. Mol. Cell. Cardiol. 13: 457–469 (1981)
Wit, A. L., Rosen, M. R., Hoffman, B. F.: Electrophysiology and pharmacology of cardiac arrhythmias. II. Relationship of normal and abnormal electrical activity of cardiac fibers to the genesis of arrhythmia. A. Automaticity. Am. Heart. J. 88: 515–524 (1974)
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Kiyosue, T., Arita, M. Magnesium restores high K-induced inactivation of the fast Na channel in guinea pig ventricular muscle. Pflugers Arch. 395, 78–80 (1982). https://doi.org/10.1007/BF00584973
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DOI: https://doi.org/10.1007/BF00584973