Ion channels in smooth muscle: regulation by the sarcoplasmic reticulum and mitochondria.
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.
Chalmers
Susan
S
Division of Physiology and Pharmacology, Strathclyde Institute of Pharmacy and Biomedical Sciences, University of Strathclyde, 27 Taylor Street, Glasgow G4 0NR, UK.
Olson
Marnie L
ML
MacMillan
Debbi
D
Rainbow
Richard D
RD
McCarron
John G
JG
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*
D053496:Inositol 1,4,5-Trisphosphate Receptors; D007473:Ion Channels; D019837:Ryanodine Receptor Calcium Release Channel; D002118:Calcium