Abstract
Three, non-cytosolic Ca2+ pools were characterized in intact PC12 cells. The first pool, sensitive to both inositol 1,4,5-trisphosphate and caffeine (Zacchetti, D., Clementi, E., Fasolato, C., Zottini, M., Grohovaz, F., Fumagalli, G., Pozzan, T., and Meldolesi, J. (1991) J. Biol. Chem. 266, 20152-20158) accounts for ≅200 μM of Ca2+/liter of cell water (<30% of total exchangeable Ca2+) and takes up Ca2+ from the cytosol via a Ca2+-ATPase, blocked by thapsigargin. A second pool, ≅400 μM/liter, is insensitive to both inositol 1,4,5-trisphosphate, caffeine, and thapsigargin and is released by the Ca2+ ionophore ionomycin. This pool is probably heterogeneous and its intracellular localization and physiological roles remain undefined. The third pool, ≅170 μmoles of Ca2+/liter, was discharged by the combination of ionomycin together with a substance that collapsed intracellular pH gradients, such as monensin or NH4C1. This indicates that the pool is acidic, at variance with the first two. When exocytosis was stimulated, the size of this pool declined, indicating its primary residence within secretory granules. In the conditions of our experiments no major transfer of Ca2+ among the pools seemed to occur. This is the first comprehensive description of non-cytosolic Ca2+ pools investigated in intact neurosecretory cells by non-invasive procedures.
| Original language | English |
|---|---|
| Pages (from-to) | 20159-20167 |
| Number of pages | 9 |
| Journal | Journal of Biological Chemistry |
| Volume | 266 |
| Issue number | 30 |
| Publication status | Published - 1991 |
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ASJC Scopus subject areas
- Biochemistry
Cite this
Intracellular Ca2+ pools in PC12 cells : Three intracellular pools are distinguished by their turnover and mechanisms of Ca2+ accumulation, storage, and release. / Fasolato, Cristina; Zottini, Michela; Clementi, Emilio; Zacchetti, Daniele; Meldolesi, Jacopo; Pozzan, Tullio.
In: Journal of Biological Chemistry, Vol. 266, No. 30, 1991, p. 20159-20167.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Intracellular Ca2+ pools in PC12 cells
T2 - Three intracellular pools are distinguished by their turnover and mechanisms of Ca2+ accumulation, storage, and release
AU - Fasolato, Cristina
AU - Zottini, Michela
AU - Clementi, Emilio
AU - Zacchetti, Daniele
AU - Meldolesi, Jacopo
AU - Pozzan, Tullio
PY - 1991
Y1 - 1991
N2 - Three, non-cytosolic Ca2+ pools were characterized in intact PC12 cells. The first pool, sensitive to both inositol 1,4,5-trisphosphate and caffeine (Zacchetti, D., Clementi, E., Fasolato, C., Zottini, M., Grohovaz, F., Fumagalli, G., Pozzan, T., and Meldolesi, J. (1991) J. Biol. Chem. 266, 20152-20158) accounts for ≅200 μM of Ca2+/liter of cell water (<30% of total exchangeable Ca2+) and takes up Ca2+ from the cytosol via a Ca2+-ATPase, blocked by thapsigargin. A second pool, ≅400 μM/liter, is insensitive to both inositol 1,4,5-trisphosphate, caffeine, and thapsigargin and is released by the Ca2+ ionophore ionomycin. This pool is probably heterogeneous and its intracellular localization and physiological roles remain undefined. The third pool, ≅170 μmoles of Ca2+/liter, was discharged by the combination of ionomycin together with a substance that collapsed intracellular pH gradients, such as monensin or NH4C1. This indicates that the pool is acidic, at variance with the first two. When exocytosis was stimulated, the size of this pool declined, indicating its primary residence within secretory granules. In the conditions of our experiments no major transfer of Ca2+ among the pools seemed to occur. This is the first comprehensive description of non-cytosolic Ca2+ pools investigated in intact neurosecretory cells by non-invasive procedures.
AB - Three, non-cytosolic Ca2+ pools were characterized in intact PC12 cells. The first pool, sensitive to both inositol 1,4,5-trisphosphate and caffeine (Zacchetti, D., Clementi, E., Fasolato, C., Zottini, M., Grohovaz, F., Fumagalli, G., Pozzan, T., and Meldolesi, J. (1991) J. Biol. Chem. 266, 20152-20158) accounts for ≅200 μM of Ca2+/liter of cell water (<30% of total exchangeable Ca2+) and takes up Ca2+ from the cytosol via a Ca2+-ATPase, blocked by thapsigargin. A second pool, ≅400 μM/liter, is insensitive to both inositol 1,4,5-trisphosphate, caffeine, and thapsigargin and is released by the Ca2+ ionophore ionomycin. This pool is probably heterogeneous and its intracellular localization and physiological roles remain undefined. The third pool, ≅170 μmoles of Ca2+/liter, was discharged by the combination of ionomycin together with a substance that collapsed intracellular pH gradients, such as monensin or NH4C1. This indicates that the pool is acidic, at variance with the first two. When exocytosis was stimulated, the size of this pool declined, indicating its primary residence within secretory granules. In the conditions of our experiments no major transfer of Ca2+ among the pools seemed to occur. This is the first comprehensive description of non-cytosolic Ca2+ pools investigated in intact neurosecretory cells by non-invasive procedures.
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UR - http://www.scopus.com/inward/citedby.url?scp=0025919762&partnerID=8YFLogxK
M3 - Article
VL - 266
SP - 20159
EP - 20167
JO - Journal of Biological Chemistry
JF - Journal of Biological Chemistry
SN - 0021-9258
IS - 30
ER -