Local Ca(2+) signaling and EC coupling in heart: Ca(2+) sparks and the regulation of the [Ca(2+)](i) transient.
The elementary event of Ca(2+) release in heart is the Ca(2+) spark. It occurs at a low rate during diastole, activated only by the low cytosolic [Ca(2+)](i). Synchronized activation of many sparks is due to the high local [Ca(2+)](i) in the region surrounding the sarcoplasmic reticulum (SR) Ca(2+) release channels and is responsible for the systolic [Ca(2+)](i) transient. The biophysical basis of this calcium signaling is discussed. Attention is placed on the local organization of the ryanodine receptors (SR Ca(2+) release channels, RyRs) and the other proteins that underlie and modulate excitation-contraction (EC) coupling. A brief review of specific elements that regulate SR Ca(2+) release (including SR lumenal Ca(2+) and coupled gating of RyRs) is presented. Finally integrative calcium signaling in heart is presented in the context of normal heart function and heart failure.
Guatimosim
Silvia
S
Medical Biotechnology Center and Institute of Molecular Cardiology, University of Maryland Biotechnology Institute, 725 W. Lombard Street, Baltimore, MD 21201, USA.
Dilly
Keith
K
Santana
L Fernando
LF
Saleet Jafri
M
M
Sobie
Eric A
EA
Lederer
W J
WJ
D000818:Animals; D002118:Calcium / Q000378:metabolism*; D020746:Calcium Channels, L-Type / Q000378:metabolism; D020013:Calcium Signaling / Q000502:physiology*; D006168:Guinea Pigs; D006333:Heart Failure / Q000209:etiology / Q000378:metabolism; D009206:Myocardium / Q000378:metabolism*; D032383:Myocytes, Cardiac / Q000378:metabolism*; D051381:Rats; D019837:Ryanodine Receptor Calcium Release Channel / Q000378:metabolism
D020746:Calcium Channels, L-Type; D019837:Ryanodine Receptor Calcium Release Channel; D002118:Calcium