title: Ion channels in smooth muscle: regulation by the sarcoplasmic reticulum and mitochondria.
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.
authors.affiliation: Division of Physiology and Pharmacology, Strathclyde Institute of Pharmacy and Biomedical Sciences, University of Strathclyde, 27 Taylor Street, Glasgow G4 0NR, UK.
authors.forename: Susan
authors.initials: S
authors.lastname: Chalmers
authors.forename: Marnie L
authors.initials: ML
authors.lastname: Olson
authors.forename: Debbi
authors.initials: D
authors.lastname: MacMillan
authors.forename: Richard D
authors.initials: RD
authors.lastname: Rainbow
authors.forename: John G
authors.initials: JG
authors.lastname: McCarron
mesh_terms: D000818:Animals; D002118:Calcium / Q000378:metabolism; D020013:Calcium Signaling; D002462:Cell Membrane / Q000378:metabolism; D053496:Inositol 1,4,5-Trisphosphate Receptors / Q000378:metabolism; D007473:Ion Channels / Q000378:metabolism*; D008928:Mitochondria / Q000378:metabolism*; D009130:Muscle, Smooth / Q000378:metabolism*; D019837:Ryanodine Receptor Calcium Release Channel / Q000378:metabolism; D012519:Sarcoplasmic Reticulum / Q000378:metabolism*
chemical_list: D053496:Inositol 1,4,5-Trisphosphate Receptors; D007473:Ion Channels; D019837:Ryanodine Receptor Calcium Release Channel; D002118:Calcium