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Analysis of Tubular Membrane Networks in Cardiac Myocytes from Atria and Ventricles
Published on: October 15, 2014
Ion channels in smooth muscle: regulation by the sarcoplasmic reticulum and mitochondria
Susan Chalmers1, Marnie L Olson, Debbi MacMillan
1Division of Physiology and Pharmacology, Strathclyde Institute of Pharmacy and Biomedical Sciences, University of Strathclyde, 27 Taylor Street, Glasgow G4 0NR, UK.
Abstract:
In smooth muscle, Ca(2+) regulates cell division, growth and cell death as well as providing the main trigger for contraction. Ion channels provide the major access route to elevate the cytoplasmic Ca(2+) concentration ([Ca(2+)](c)) in smooth muscle by permitting Ca(2+) entry across the plasma membrane and release of the ion from intracellular Ca(2+) stores. The control of [Ca(2+)](c) relies on feedback modulation of the entry and release channels by Ca(2+) itself. Local rises in [Ca(2+)](c) may promote or inhibit channel activity directly or indirectly. The latter may arise from Ca(2+) regulation of ionic conductances in the plasma membrane to provide control of cell excitability and so [Ca(2+)](c) entry. Organelles such as mitochondria may also contribute significantly to the feedback regulation of ion channel activity by the control of Ca(2+) or redox status of the cell. This brief review describes the feedback regulation of Ca(2+) release from the internal Ca(2+) store and of plasma membrane excitability in smooth muscle.
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