Invited Review: Mechanisms of calcium handling in smooth muscles.
Sanders, Kenton M.
Department of Physiology and Cell Biology, University of Nevada School of
Medicine, Reno, Nevada 89557
APStracts 8:0293A, 2001.
The concentration of cytoplasmic Ca2+ regulates the contractile state of smooth muscle
cells and tissues. Elevations in global cytoplasmic Ca2+ resulting in contraction are
accomplished by Ca2+ entry and release from intracellular stores. Pathways for Ca2+
entry include dihydropyridine-sensitive and -insensitive Ca2+ channels and receptor and
store-operated nonselective channels permeable to Ca2+. Intracellular release from the
sarcoplasmic reticulum (SR) is accomplished by ryanodine and inositol trisphosphate
receptors. The impact of Ca2+ entry and release on cytoplasmic concentration is
modulated by Ca2+ reuptake into the SR, uptake into mitochondria, and extrusion into
the extracellular solution. Highly localized Ca2+ transients (i.e., sparks and puffs)
regulate ionic conductances in the plasma membrane, which can provide feedback to cell
excitability and affect Ca2+ entry. This short review describes the major transport
mechanisms and compartments that are utilized for Ca2+ handling in smooth muscles.
APS Manuscript Number A446-1.
Article publication pending J Appl Physiol
ISSN 1080-4757 Copyright 2001 The American Physiological Society.
Published in APStracts on 18 June 2001