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The resting membrane parameters of human intercostal muscle at low, normal, and high extracellular potassium
Author(s) -
Kwieciński 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.880070110
Subject(s) - intercostal muscle , extracellular , potassium , anatomy , human muscle , chemistry , medicine , skeletal muscle , biochemistry , respiratory system , organic chemistry
Membrane parameters at the respective resting potentials in low, normal, and high extracellular potassium solutions were determined in intercostal muscle fibers from 15 patients with no known neuromuscular disease. In synthetic interstitial fluid (normal potassium concentration 3.5 mmol/liter), we found the following mean values: resting membrane potential RP = ‐−83.3 mV, space constant γLD = 2364 μm, fiber diameter d = 49.3 μm, fiber input resistance R in = 795 KΩ, specific membrane capacitance C m = 4.7 μF/cm 2 , and specific membrane resistance R m = 5970 Ω·cm 2 . The specific membrane conductance was g m = 168 m̈S/cm 2 , 76% of it being chloride conductance, 24% being potassium conductance. The dependence of the membrane parameters on the extracellular potassium concentration followed the predictions by the constant field theory. There was no indication of active chloride transport. The resting membrane conductance decreased with temperature with a Q 10 of 1.3. Excitability parameters were nearly independent of temperature between 37 and 27°C.