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Membrane currents in human intercostal muscle at varied extracellular potassium
Author(s) -
Kwiecinski Hubert,
LehmannHorn Frank,
Rüdel Reinhardt
Publication year - 1984
Publication title -
muscle and nerve
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.025
H-Index - 145
eISSN - 1097-4598
pISSN - 0148-639X
DOI - 10.1002/mus.880070608
Subject(s) - intercostal muscle , extracellular , potassium , anatomy , chemistry , medicine , biophysics , biology , biochemistry , respiratory system , organic chemistry
Hyperpolarizing and depolarizing square steps were imposed on the membrane potential of excised human intercostal muscle fibers by means of a 3‐microelectrode voltage clamp. The steady‐state amplitudes of the membrane currents inducing such steps were investigated as a function of the membrane potential, while the muscle was bathed in solutions varying in potassium content (K e = 1, 3.5, 7, 20, and 60 m M ). At all potassium concentrations, the membrane acted as a rectifier, both in the inward‐ and outward‐going directions. Inward currents were much reduced when K e was lowered from 3.5 to 1 m M , and were increased when K e was raised beyond 3.5 m M . The delayed outward current was reduced when K e was increased from 3.5 m M to 7 m M and higher potassium concentration. The results were qualitatively similar to those reported for rat skeletal muscle.