Premium
Regulation of sarcoplasmic reticulum Ca 2+ leak by cytosolic Ca 2+ in rabbit ventricular myocytes
Author(s) -
Bovo Elisa,
Mazurek Stefan R.,
Blatter Lothar A.,
Zima Aleksey V.
Publication year - 2011
Publication title -
the journal of physiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.802
H-Index - 240
eISSN - 1469-7793
pISSN - 0022-3751
DOI - 10.1113/jphysiol.2011.214171
Subject(s) - ryanodine receptor , endoplasmic reticulum , myocyte , cytosol , contraction (grammar) , chemistry , calcium , biophysics , medicine , endocrinology , biochemistry , biology , enzyme , organic chemistry
Non‐technical summary Contraction and relaxation of the heart strongly depend on calcium (Ca 2+ ) stored in the sarcoplasmic reticulum (SR). Ca 2+ stored within the SR is determined by the balance between Ca 2+ uptake and Ca 2+ leak that occurs mainly via Ca 2+ release channels, called ryanodine receptors (RyRs). Alterations in the RyR activity can lead to enhanced SR Ca 2+ leak and arrhythmias. Ca 2+ tightly regulates the RyR activity from both sides of the SR (cytosolic and luminal). In this work, we studied the effects of cytosolic Ca 2+ on SR Ca 2+ leak in isolated ventricular myocytes. Elevation of cytosolic Ca 2+ increased SR Ca 2+ leak by a direct activation of RyRs. In intact myocytes, at the end of contraction and at the beginning of the relaxation phase, SR Ca 2+ leak remains relatively constant due to the coordinated regulation of RyRs by cytosolic and luminal Ca 2+ . Thus, this dual regulation of the RyR contributes to the control of the SR Ca 2+ content, preventing excessive loss of Ca 2+ that could lead to pathological conditions such as cardiac arrhythmia.