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Electrochemical potentials of potassium in skeletal muscle under different metabolic states
Author(s) -
Khuri Raja N.,
Agulian Samuel K.,
AbdulnourNakhoul Solange,
Nakhoul Nazih L.
Publication year - 1992
Publication title -
journal of cellular physiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.529
H-Index - 174
eISSN - 1097-4652
pISSN - 0021-9541
DOI - 10.1002/jcp.1041530314
Subject(s) - potassium , skeletal muscle , electrochemistry , chemistry , biophysics , biology , anatomy , electrode , organic chemistry
Intracellular potassium and membrane potential were measured simultaneously by means of double‐barrelled liquid ion‐exchange microelectrodes in single fibers of rat thigh muscle in vivo in rats maintained in seven different metabolic states. The K + equilibrium potential (E k ) was more negative than the simulataneously measured membrane potential (E m ) in the normal state by 18.4 mV. K + loading, acute and chronic, resulted in depolarization of E m due to increased serum K + (hyperkalemia) with no increase in intracellular K + . K + depletion resulted in hyperpolarization of E m as plasma K + decreased proportionately more than intracellular K + . Low Na + diet had no effect. Intracellular K + was decreased in acute acidosis but not in the chronic state. Thus K + depletion and acute acidosis are associated with intracellular K + decrease. The fact that hyperpolarization exists in the former and not the latter is a reflection that hypokalemia accompanies the former condition. The hyperpolarizing states of K + depletion and chronic acidosis are accompanied by decreased excitability and muscle weakness. © 1992 Wiley‐Liss, Inc.