[Microscopic mechanism of excitation-contraction coupling in cardiac myocytes].
Cardiac excitation-contraction coupling (ECC) is, in essence, a communication process between sarcolemmal voltage-dependent L-type calcium channels (LCCs) and ryanodine receptors (RyRs) of sarcoplasmic reticulum (SR) by the mechanism of calcium-induced calcium release (CICR). Recent advances displayed more information about the microscopic signaling between LCCs and RyRs. In calcium release couplons, the calcium influx through the opening of LCCs by membrane depolarization forms calcium sparklets locally which then act on the adjacent SR RyRs. Stochastic activation of RyRs discharges calcium sparks from different calcium couplons, which summate into global calcium transients. Therefore, ignition of calcium sparks by calcium sparklets constitutes the elementary events in ECC. This review focuses on the intermolecular signaling between LCCs and RyRs, to describe the microscopic view of CICR and ECC.
Shen
Jian-Xin
JX
Department of Physiology, Shantou University Medical College, Shantou.
Han
Tai-Zhen
TZ
Cheng
He-Ping
HP
D000818:Animals; D020746:Calcium Channels, L-Type / Q000378:metabolism*; D020013:Calcium Signaling; D006321:Heart / Q000502:physiology; D006801:Humans; D015640:Ion Channel Gating; D018613:Microscopy, Confocal; D009200:Myocardial Contraction; D032383:Myocytes, Cardiac / Q000502:physiology*; D019837:Ryanodine Receptor Calcium Release Channel / Q000502:physiology*; D012508:Sarcolemma / Q000502:physiology; D012519:Sarcoplasmic Reticulum / Q000187:drug effects / Q000502:physiology; D019831:Sodium-Calcium Exchanger / Q000502:physiology
D020746:Calcium Channels, L-Type; D019837:Ryanodine Receptor Calcium Release Channel; D019831:Sodium-Calcium Exchanger