Control of calcium oscillations by membrane fluxes
AUTOR(ES)
Sneyd, J.
FONTE
National Academy of Sciences
RESUMO
It is known that Ca2+ influx plays an important role in the modulation of inositol trisphosphate-generated Ca2+ oscillations, but controversy over the mechanisms underlying these effects exists. In addition, the effects of blocking membrane transport or reducing Ca2+ entry vary from one cell type to another; in some cell types oscillations persist in the absence of Ca2+ entry (although their frequency is affected), whereas in other cell types oscillations depend on Ca2+ entry. We present theoretical and experimental evidence that membrane transport can control oscillations by controlling the total amount of Ca2+ in the cell (the Ca2+ load). Our model predicts that the cell can be balanced at a point where small changes in the Ca2+ load can move the cell into or out of oscillatory regions, resulting in the appearance or disappearance of oscillations. Our theoretical predictions are verified by experimental results from HEK293 cells. We predict that the role of Ca2+ influx during an oscillation is to replenish the Ca2+ load of the cell. Despite this prediction, even during the peak of an oscillation the cell or the endoplasmic reticulum may not be measurably depleted of Ca2+.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=337063Documentos Relacionados
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