A possible role of inwardly rectifying K+ channels in chick myoblast differentiation

Ki Soon Shin, Jae Yong Park, Hyockman Kwon, Chin Ha Chung, Man Sik Kang

Research output: Contribution to journalArticlepeer-review

18 Citations (Scopus)

Abstract

We examined the developmental change of inwardly rectifying K+ channels (IRK) and its possible role in myogenesis. Northern blot analysis revealed an increase in the level of IRK mRNA during myogenesis. Accordingly, IRK current was not detectable in replicating myoblasts but first appeared in aligned myoblasts that were competent for fusion and gradually increased thereafter. The time course change of IRK activity was closely related to the increase in resting membrane potential during myogenesis. Application of 0.5 mM Ba2+ to the bath depolarized the membrane and blocked IRK currents dramatically but not outwardly rectifying K+ currents. Myoblasts devoid of IRK had low resting K+ permeability, whereas myotubes that possess IRK had high resting K+ permeability. In some aligned myoblasts, anomalous hyperpolarization was elicited by increasing extracellular K+ concentration, which may be attributable to the increased conductance of IRK. Noteworthy was the fact that maximal fusion was obtained at this range of K+ concentration. These findings imply that IRK is responsible for the change in the K+ permeability during chick myogenesis, which may provide a larger driving force for Ca2+ influx that is a prerequisite for myoblast fusion.

Original languageEnglish
Pages (from-to)C894-C900
JournalAmerican Journal of Physiology - Cell Physiology
Volume272
Issue number3 41-3
DOIs
Publication statusPublished - 1997 Mar
Externally publishedYes

Keywords

  • calcium influx
  • myogenesis
  • permeability
  • resting membrane potential

ASJC Scopus subject areas

  • Physiology
  • Cell Biology

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