Affordable Access

Publisher Website

The role of the sodium-calcium exchanger for calcium extrusion in coronary arteries

Life Sciences
Publication Date
DOI: 10.1016/s0024-3205(00)00646-9
  • A23187
  • Calcium
  • Sodium-Calcium Exchanger
  • Endothelium-Derived Relaxing Factor
  • Pig Coronary Arteries


Abstract Calcium ionophores, such as the A23187, cause endothelium-dependent relaxation of arterial strips with intact endothelium, whereas the effect of the ionophore should result from the combination of a relaxation caused by the endothelium-dependent factors and of a contraction of the smooth muscles. In addition, the application of a calcium ionophore to a strip of pig coronary arteries without endothelium does not change cytosolic free calcium concentration and force developed by the smooth muscle cells. To explain these paradoxes, the hypothesis that active calcium extrusion would match the entry of extracellular calcium caused by the ionophore was tested. We see that the sodium-calcium exchanger extrudes calcium that enters the smooth muscle cells in the absence of the ionophore. This exchanger is efficient enough to expel the increased influx of calcium created by the additional calcium carriers formed by the ionophore. This explains the inefficiency of calcium ionophores to increase cytosolic free calcium of smooth muscle cells and consequently, the fact that the ionophore does not cause a contraction of a strip without endothelium. This makes evident that a calcium ionophore fully relaxes, in an endothelium-dependent manner, an intact strip of porcine coronary artery.

There are no comments yet on this publication. Be the first to share your thoughts.


Seen <100 times

More articles like this

Calcium extrusion by the sodium-calcium exchanger...

on Annals of the New York Academy... 1991

Calcium Extrusion During Aftercontractions in Card...

on Journal of Molecular and Cellu... Jan 01, 2000

Calcium extrusion during aftercontractions in card...

on Journal of molecular and cellu... January 2000
More articles like this..