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Intercellular Ca 2+ waves in rat heart muscle
Author(s) -
Lamont Christine,
Luther Paul W.,
Balke C. William,
Wier W. Gil
Publication year - 1998
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 - 10.1111/j.1469-7793.1998.669bd.x
Subject(s) - gap junction , connexin , intracellular , biophysics , cell junction , calcium , myocyte , cardiac muscle , cell , stimulation , chemistry , biology , microbiology and biotechnology , anatomy , endocrinology , biochemistry , organic chemistry
1 Confocal laser scanning microscopy was used to visualize intercellular transmission of Ca 2+ waves in intact rat ventricular trabeculae micro‐injected with the calcium indicator fluo‐3. 2 Ca 2+ waves usually failed to be transmitted from cell to cell. At identified individual end‐to‐end cell contacts, successful transmission interspersed with failure, which sometimes occurred despite an apparent small spritz of Ca 2+ between cells. The probability of cell to cell transmission ( P tran ) was 0.13. 3 Ca 2+ waves arose preferentially near junctions of connected cells, where connexin‐43 was found, but randomly in enzymatically disconnected heart cells. 4 β‐Adrenergic stimulation significantly increased P tran (to 0.22) and heptanol, an uncoupler of gap junction channels, significantly decreased it (to 0.045). 5 In regions of high [Ca 2+ ] i due to damage, wave frequency decreased markedly with each cell‐cell junction passed. 6 The Ca 2+ permeability of cardiac gap junctions may be regulated, and the low ability of cardiac gap junctions to transmit Ca 2+ may help control the spread of Ca 2+ from damaged regions.