Modulation of a potassium conductance in developing skeletal muscle

Am J Physiol. 1995 Feb;268(2 Pt 1):C490-5. doi: 10.1152/ajpcell.1995.268.2.C490.


K+ conductances dominate and potentially modulate the resting potential of skeletal muscle cells. The expression and modulation of a major K+ conductance were examined during in vitro differentiation of the mouse myoblast cell line C2C12. The inwardly rectifying K+ conductance (IKi) increased from unmeasurable levels in undifferentiated myoblasts to approximately 1.56 +/- 0.51 nA (n = 17) in myoballs derived from myotubes at 5 days after induction of differentiation. The inward rectifier was subject to modulation by intracellular signals. Exposure of cytoplasm to guanosine 5'-O-(3-thiotriphosphate) during whole cell recording produced a concentration (5-100 microM)- and time (1-20 min)-dependent inhibition of the mean conductance. Elevation of intracellular free Ca2+ (> 200 nM) also inhibited IKi. These findings demonstrate a potential mechanism for modulation of the resting potential of muscle fibers via the control of skeletal muscle IKi.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Calcium / physiology
  • Cell Line
  • Electric Conductivity
  • Guanosine 5'-O-(3-Thiotriphosphate) / pharmacology
  • Mice
  • Muscle Development*
  • Muscle, Skeletal / cytology
  • Muscle, Skeletal / growth & development*
  • Muscle, Skeletal / physiology*
  • Potassium / physiology*


  • Guanosine 5'-O-(3-Thiotriphosphate)
  • Potassium
  • Calcium