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Pflügers Archiv

, Volume 395, Issue 1, pp 78–80 | Cite as

Magnesium restores high K-induced inactivation of the fast Na channel in guinea pig ventricular muscle

  • Tatsuto Kiyosue
  • Makoto Arita
Excitable Tissues and Central Nervous Physiology Letters and Notes

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”.

Key words

Magnesium Ventricular muscle Maximum rate of rise Na inactivation curve Surface charge 

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Copyright information

© Springer-Verlag 1982

Authors and Affiliations

  • Tatsuto Kiyosue
    • 1
  • Makoto Arita
    • 1
  1. 1.Department of PhysiologyFaculty of Medicine Medical College of OitaOitaJapan

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