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Calcium events in smooth muscles and their interstitial cells; physiological roles of sparks
Author(s) -
Bolton Tom B.
Publication year - 2006
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.2005.095604
Subject(s) - ryanodine receptor , depolarization , calcium , chemistry , myocyte , t type calcium channel , inositol , contraction (grammar) , smooth muscle , muscle contraction , calcium signaling , microbiology and biotechnology , receptor , voltage dependent calcium channel , motility , inositol trisphosphate , biophysics , biology , anatomy , endocrinology , biochemistry , organic chemistry
The observation of spontaneous sporadic releases of packets of stored calcium made 20 years ago has opened up a number of new concepts in smooth muscle physiology: (1) the calcium release sites are ryanodine and inositol 1,4,5‐trisphosphate (IP 3 ) receptor channels which contribute to cell‐wide increases in [Ca 2 + ] i in response to cell depolarization, activation of IP 3 ‐generating receptors, or other stimuli; (2) changes in [Ca 2 + ] i act back on the cell membrane to activate or modulate K + , Cl − and cation channel activity so affecting contraction, in arterial smooth muscle for example affecting blood pressure; (3) IP 3 production is voltage dependent and is believed to contribute to pacemaker potentials and to refractory periods which control the rhythmical motility of many hollow organs. Most smooth muscle tissues contain interstitial cells (ICs) in addition to contractile smooth muscle cells (SMCs). The interactions of these internal mechanisms, and in turn the interactions of SMCs and ICs in various smooth muscle tissues, are major factors in determining the unique physiological profiles of individual smooth muscles.