Peptide and protein modulation of local Ca2+ release events in permeabilized skeletal muscle fibers

Biol Res. 2004;37(4):613-6. doi: 10.4067/s0716-97602004000400016.


Local discrete elevations in myoplasmic Ca2+ (Ca2+ sparks) arise from the opening of a small group of RyRs. Summation of a large number of Ca2+ sparks gives rise to the whole cell Ca2+ transient necessary for muscle contraction, Unlike sarcoplasmic reticulum vesicle preparations and isolated single channels in artificial membranes, the study of Ca2+ sparks provides a means to understand the regulation of a small group of RyRs in the environment of a functionally intact triad and in the presence of endogenous regulatory proteins. To gain insight into the mechanisms that regulate the gating of RyRs we have utilized laser scanning confocal microscopy to measure Ca2+ sparks in permeabilized frog skeletal muscle fibers. This review summarizes our recent studies using both exogenous (ImperatoxinA and domain peptides) and endogenous (calmodulin) modulators of RyR to gain insight into the number of RyR Ca2+ release channels underlying a Ca2+ spark, how domain-domain interactions within RyR regulate the functional state of the channel as well as gating mechanisms of RyR in living muscle fibers.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, U.S. Gov't, P.H.S.
  • Review

MeSH terms

  • Animals
  • Calcium / metabolism*
  • Calmodulin / metabolism*
  • Microscopy, Confocal
  • Muscle Contraction / drug effects
  • Muscle Contraction / physiology
  • Muscle Fibers, Skeletal / drug effects
  • Muscle Fibers, Skeletal / metabolism*
  • Muscle, Skeletal / drug effects
  • Muscle, Skeletal / metabolism*
  • Permeability
  • Protein Structure, Tertiary
  • Ryanodine Receptor Calcium Release Channel / drug effects
  • Ryanodine Receptor Calcium Release Channel / metabolism
  • Scorpion Venoms / pharmacology*


  • Calmodulin
  • Ryanodine Receptor Calcium Release Channel
  • Scorpion Venoms
  • imperatoxin A
  • Calcium