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Ionic conductances involved in generation and propagation of electrical slow waves in phasic gastrointestinal muscles
Author(s) -
Sanders K. M.,
Koh S. D.,
Ördög T.,
Ward S. M.
Publication year - 2004
Publication title -
neurogastroenterology and motility
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.489
H-Index - 105
eISSN - 1365-2982
pISSN - 1350-1925
DOI - 10.1111/j.1743-3150.2004.00483.x
Subject(s) - interstitial cell of cajal , pacemaker potential , depolarization , biophysics , intracellular , chemistry , conductance , calcium , ion channel , neuroscience , biology , smooth muscle , physics , medicine , receptor , biochemistry , condensed matter physics
Considerable work has led many to conclude that interstitial cells of Cajal (ICC) are the pacemaker cells of the gastrointestinal (GI) tract. These cells form electrically coupled networks within the pacemaker regions of the GI tract, and ICC are electrically coupled to smooth muscle cells. ICC express unique ion channels that periodically produce inward (pacemaker) currents. Recent work has suggested that the inward current is produced by a calcium (Ca 2+ )‐regulated, nonselective cation conductance. Channels responsible for this conductance oscillate in open probability in response to the periodic drop in intracellular Ca 2+ concentration during the slow wave cycle. Pacemaker activity generates slow waves that are propagated actively through ICC networks. Depolarization coordinates the pacemaker activity through the ICC network by activating a dihydropyridine‐resistant Ca 2+ conductance. Entry of small amounts of Ca 2+ into ICC entrains spontaneous pacemaker activity and produces cell‐to‐cell propagation of slow waves. This review discusses the mechanisms and conductances involved in generation and propagation of electrical slow waves in ICC.