Calcium transients in aequorin-injected frog cardiac muscle

@article{Allen1978CalciumTI,
  title={Calcium transients in aequorin-injected frog cardiac muscle},
  author={David G. Allen and John R. Blinks},
  journal={Nature},
  year={1978},
  volume={273},
  pages={509-513}
}
The Ca2+-sensitive bioluminescent protein aequorin was microinjected into cells of frog at rial trabeculae to study intracellular calcium transients associated with excitation–contraction coupling. The amplitude of the aequorin signal increased with extracellular Ca2+ concentration and stimulus frequency, but decreased with stretch. Isoprenaline and acetylstrophanthidin both increased the amplitude, but had strikingly different effects on the time course of the signal.