Abstract
Parathyroid hormone secretion is exquisitely sensitive to small changes in serum Ca2+ concentration, and these responses are transduced via the Ca2+-sensing receptor (CaR). We utilized heterologous expression in HEK-293 cells to determine the effects of small, physiologically relevant perturbations in extracellular Ca2+ on CaR signaling via phosphatidylinositol-phospholipase C, using changes in fura 2 fluorescence to quantify intracellular Ca2+. Chronic exposure of CaR-transfected cells to Ca2+ in the range from 0.5 to 3 mM modulated the resting intracellular Ca2+ concentration and the subsequent cellular responses to acute extracellular Ca2+ perturbations but had no effect on thapsigargin-sensitive Ca2+ stores. Modest, physiologically relevant increases in extracellular Ca2+ concentration (0.5 mM increments) caused sustained (30-40 min) low-frequency oscillations of intracellular Ca2+ (∼45 s peak to peak interval). Oscillations were eliminated by 1 μM thapsigargin but were insensitive to protein kinase inhibitors (staurosporine, KN-93, or bisindolylmaleimide I). Staurosporine did increase the fraction of cells oscillating at a given extracellular Ca2+ concentration. Serum Ca2+ concentrations thus chronically regulate cells expressing CaR, and small perturbations in extracellular Ca2+ alter both resting intracellular Ca2+ as well as Ca2+ dynamics.
| Original language | English (US) |
|---|---|
| Journal | American Journal of Physiology - Cell Physiology |
| Volume | 280 |
| Issue number | 6 49-6 |
| State | Published - 2001 |
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Keywords
- Calcium oscillations
- Fura 2
- HEK-293 cells
- Intracellular calcium
- Protein kinase inhibitors
- Thapsigargin-sensitive calcium stores
ASJC Scopus subject areas
- Clinical Biochemistry
- Cell Biology
- Physiology
- Physiology (medical)
Cite this
Calcium-sensing receptor activation induces intracellular calcium oscillations. / Breitwieser, Gerda E.; Gama, Lucio.
In: American Journal of Physiology - Cell Physiology, Vol. 280, No. 6 49-6, 2001.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Calcium-sensing receptor activation induces intracellular calcium oscillations
AU - Breitwieser, Gerda E.
AU - Gama, Lucio
PY - 2001
Y1 - 2001
N2 - Parathyroid hormone secretion is exquisitely sensitive to small changes in serum Ca2+ concentration, and these responses are transduced via the Ca2+-sensing receptor (CaR). We utilized heterologous expression in HEK-293 cells to determine the effects of small, physiologically relevant perturbations in extracellular Ca2+ on CaR signaling via phosphatidylinositol-phospholipase C, using changes in fura 2 fluorescence to quantify intracellular Ca2+. Chronic exposure of CaR-transfected cells to Ca2+ in the range from 0.5 to 3 mM modulated the resting intracellular Ca2+ concentration and the subsequent cellular responses to acute extracellular Ca2+ perturbations but had no effect on thapsigargin-sensitive Ca2+ stores. Modest, physiologically relevant increases in extracellular Ca2+ concentration (0.5 mM increments) caused sustained (30-40 min) low-frequency oscillations of intracellular Ca2+ (∼45 s peak to peak interval). Oscillations were eliminated by 1 μM thapsigargin but were insensitive to protein kinase inhibitors (staurosporine, KN-93, or bisindolylmaleimide I). Staurosporine did increase the fraction of cells oscillating at a given extracellular Ca2+ concentration. Serum Ca2+ concentrations thus chronically regulate cells expressing CaR, and small perturbations in extracellular Ca2+ alter both resting intracellular Ca2+ as well as Ca2+ dynamics.
AB - Parathyroid hormone secretion is exquisitely sensitive to small changes in serum Ca2+ concentration, and these responses are transduced via the Ca2+-sensing receptor (CaR). We utilized heterologous expression in HEK-293 cells to determine the effects of small, physiologically relevant perturbations in extracellular Ca2+ on CaR signaling via phosphatidylinositol-phospholipase C, using changes in fura 2 fluorescence to quantify intracellular Ca2+. Chronic exposure of CaR-transfected cells to Ca2+ in the range from 0.5 to 3 mM modulated the resting intracellular Ca2+ concentration and the subsequent cellular responses to acute extracellular Ca2+ perturbations but had no effect on thapsigargin-sensitive Ca2+ stores. Modest, physiologically relevant increases in extracellular Ca2+ concentration (0.5 mM increments) caused sustained (30-40 min) low-frequency oscillations of intracellular Ca2+ (∼45 s peak to peak interval). Oscillations were eliminated by 1 μM thapsigargin but were insensitive to protein kinase inhibitors (staurosporine, KN-93, or bisindolylmaleimide I). Staurosporine did increase the fraction of cells oscillating at a given extracellular Ca2+ concentration. Serum Ca2+ concentrations thus chronically regulate cells expressing CaR, and small perturbations in extracellular Ca2+ alter both resting intracellular Ca2+ as well as Ca2+ dynamics.
KW - Calcium oscillations
KW - Fura 2
KW - HEK-293 cells
KW - Intracellular calcium
KW - Protein kinase inhibitors
KW - Thapsigargin-sensitive calcium stores
UR - http://www.scopus.com/inward/record.url?scp=0034989929&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=0034989929&partnerID=8YFLogxK
M3 - Article
C2 - 11350736
AN - SCOPUS:0034989929
VL - 280
JO - American Journal of Physiology
JF - American Journal of Physiology
SN - 0363-6135
IS - 6 49-6
ER -