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Effects of thyroxine on transmembrane resting potentials of skeletal muscle cells in culture
Author(s) -
Sampson S. R.,
Bannett Rena R.,
Shainberg A.
Publication year - 1982
Publication title -
journal of neuroscience research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.72
H-Index - 160
eISSN - 1097-4547
pISSN - 0360-4012
DOI - 10.1002/jnr.490080404
Subject(s) - skeletal muscle , myogenesis , medicine , endocrinology , ouabain , membrane potential , myocyte , extracellular , transmembrane protein , resting potential , chemistry , biology , biochemistry , sodium , receptor , organic chemistry
The effect of thyroxine (T 4 ) was studied on the transmembrane resting potential (Em) of rat skeletal muscle cells in culture. In agreement with previous studies, we found the Em of developing muscle cells to increase with age from Day 3 to Day 7 or 8, at which time a plateau is reached. The values of Em we obtained (−65 to −75 mV) were 15–20 mV higher than those (−50 to −55 mV) reported by others. Treatment of mature myotubes with T 4 resulted in a significant increase in resting Em. There was only a slight difference between T 4 ‐treated and control cells with regard to the relation between extracellular K + concentration and resting Em. Within 20–30 min of exposure to ouabain (10 −4 –10 −3 M) resting Em of both T 4 ‐treated and control cells had fallen to about the same value. This effect was reversible. Thus, T 4 stimulates the activity of an electrogenic Na/K‐ATPase in the membrane of cultured skeletal muscle cells.