Plasticity of excitation-contraction coupling in fish cardiac myocytes

Comp Biochem Physiol A Mol Integr Physiol. 2002 Aug;132(4):827-46. doi: 10.1016/s1095-6433(02)00051-x.


Ultrastructure, molecular composition and electrophysiological properties of cardiac myocytes and functional characteristics of the fish heart suggest that cycling of extracellular Ca(2+) is generally more important than intracellular cycling of Ca(2+) stores of the sarcoplasmic reticulum (SR) in activating contraction of fish cardiac myocytes. This is especially true for the ventricle. However, prominent species-specific differences exist in cardiac excitation-contraction coupling and in the relative roles of extracellular and intracellular Ca(2+) sources among the teleostean fish. In fact, in some fish species (tunas, burbot) the SR of atrial myocytes, under certain circumstances, may act as the major source of systolic Ca(2+). These interspecific differences are obviously an outcome of evolutionary adaptation to different habitats and modes of activity in these habitats. There is also substantial intraspecific variation in the SR Ca(2+)-release-to-SL-Ca(2+) influx ratio depending on acute and chronic temperature changes. Consequently excitation-contraction coupling of the fish cardiac myocytes is not a fixed entity, but rather a highly variable and malleable process that enables fish to have an appropriate cardiac scope to exploit a diverse range of environments.

Publication types

  • Research Support, Non-U.S. Gov't
  • Review

MeSH terms

  • Acclimatization / physiology
  • Action Potentials
  • Animals
  • Calcium Channels, L-Type / metabolism
  • Calcium Signaling
  • Fishes / physiology*
  • Heart Conduction System / physiology
  • Models, Cardiovascular
  • Myocardial Contraction / physiology*
  • Potassium / metabolism
  • Sarcoplasmic Reticulum / metabolism


  • Calcium Channels, L-Type
  • Potassium