Cardiac muscle contraction

Contraction of the heart is a complex process initiated by the electrical excitation of cardiac myocytes (excitation-contraction coupling, ECC). In cardiac myocytes, Ca2+ influx induced by activation of voltage-dependent L-type Ca channels (DHP receptors) upon membrane depolarization triggers the release of Ca2+ via Ca2+ release channels (ryanodine receptors) of sarcoplasmic reticulum (SR) through a Ca2+ -induced Ca release (CICR) mechanism. Ca2+ ions released via the CICR mechanism diffuse through the cytosolic space to contractile proteins to bind to troponinC resulting in the release of inhibition induced by troponinI. The Ca2+ binding to troponinC thereby triggers the sliding of thin and thick filaments, that is, the activation of a crossbridge and subsequent cardiac force development and/or cell shortening. Recovery occurs as Ca2+ is pumped out of the cell by the Na+/Ca2+ exchanger (NCX) or is returned to the sarcoplasmic reticulum (SR) by sarco(endo)plasmic Ca2+ -ATPase (SERCA) pumps on the non-junctional region of the SR.

Organismal Systems; Circulatory system

PMID:17988210

Bers DM

Calcium cycling and signaling in cardiac myocytes.

Annu Rev Physiol 70:23-49 (2008)

PMID:11805843

Bers DM

Cardiac excitation-contraction coupling.

Nature 415:198-205 (2002)

PMID:16799263

Endoh M

Signal transduction and Ca2+ signaling in intact myocardium.

J Pharmacol Sci 100:525-37 (2006)

PMID:18981594

Endoh M

Cardiac Ca2+ signaling and Ca2+ sensitizers.

Circ J 72:1915-25 (2008)

PMID:16552170

Bers DM, Despa S

Cardiac myocytes Ca2+ and Na+ regulation in normal and failing hearts.

J Pharmacol Sci 100:315-22 (2006)

PMID:10747208

Gordon AM, Homsher E, Regnier M

Regulation of contraction in striated muscle.

Physiol Rev 80:853-924 (2000)

PMID:16701909

Phrommintikul A, Chattipakorn N

Roles of cardiac ryanodine receptor in heart failure and sudden cardiac death.

Int J Cardiol 112:142-52 (2006)

PMID:16096350

Lacinova L

Voltage-dependent calcium channels.

Gen Physiol Biophys 24 Suppl 1:1-78 (2005)

PMID:12763850

Lingrel J, Moseley A, Dostanic I, Cougnon M, He S, James P, Woo A, O'Connor K, Neumann J

Functional roles of the alpha isoforms of the Na,K-ATPase.

Ann N Y Acad Sci 986:354-9 (2003)

PMID:11294886

Berg JS, Powell BC, Cheney RE

A millennial myosin census.

Mol Biol Cell 12:780-94 (2001)

PMID:15736582

Parmacek MS, Solaro RJ

Biology of the troponin complex in cardiac myocytes.

Prog Cardiovasc Dis 47:159-76 (2004)

PMID:14659803

Yamashita H, Sugiura S, Fujita H, Yasuda S, Nagai R, Saeki Y, Sunagawa K, Sugi H

Myosin light chain isoforms modify force-generating ability of cardiac myosin by changing the kinetics of actin-myosin interaction.

Cardiovasc Res 60:580-8 (2003)