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| Predicate | Object |
|---|---|
| rdf:type | |
| lifeskim:mentions | |
| pubmed:issue |
3
|
| pubmed:dateCreated |
1996-9-19
|
| pubmed:abstractText |
Spatio-temporal aspects of Ca2+ signaling in melanotrope cells of Xenopus laevis have been studied with confocal laser-scanning microscopy. In the whole-frame scanning mode, two major intracellular Ca2+ compartments, the cytoplasm and the nucleus, were visualized. The basal [Ca2+] in the nucleus appeared to be lower than that in the cytoplasm and Ca2+ oscillations seemed to arise synchronously in both compartments. The N-type channel blocker omega-conotoxin eliminated oscillations in both regions, indicating a strong coupling between the two compartments with respect to Ca2+ dynamics. Line-scanning mode, which gives higher time resolution, revealed that the rise phase of a Ca2+ oscillation is not a continuous process but consists of 3 or 4 discrete steps. Each step can be seen as a Ca(2+)-wave starting at the cell membrane and going through the cytoplasm at a speed of 33.3 +/- 4.3 microns/s. Before the Ca(2+)-wave enters the nucleus, a delay of 120.0 +/- 24.1 ms occurred. In the nucleus, the speed of a wave was 80.0 +/- 3.0 microns/s. Treatment with the Ca(2+)-ATPase inhibitor thapsigargin (1 MicroM) almost completely eliminated the apparent difference in the basal [Ca2+] in the cytoplasm and the nucleus, reduced the delay of a Ca(2+)-wave before entering the nucleus to 79.8 +/- 8.7 ms, and diminished the nuclear wave speed to 35.0 +/- 4.9 microns/s. These results indicate that a cytoplasmic thapsigargin-sensitive ATPase near the nuclear envelope is involved in buffering Ca2+ before the Ca2+ wave enters the nucleus. After sensitizing IP3 receptors by thimerosal (10 microM) the speed of the cytoplasmic Ca(2+)-wave was increased to 70.3 +/- 3.6 microns/s, suggesting that IP3 receptors may be involved in the propagation of the cytoplasmic Ca2+ wave. Our results indicate that in melanotropes the generation and propagation of Ca2+ oscillations is a complex event involving influx of Ca2+ through N-type Ca2+ channels, propagation of the cytoplasmic Ca2+ wave through mobilization of intracellular stores and a regulated Ca2+ entry into the nucleus. We propose that Ca(2+)-binding proteins may act as a Ca2+ store for propagation of the wave in the nucleus.
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| pubmed:language |
eng
|
| pubmed:journal | |
| pubmed:citationSubset |
IM
|
| pubmed:chemical |
http://linkedlifedata.com/resource/pubmed/chemical/Calcium,
http://linkedlifedata.com/resource/pubmed/chemical/Calcium Channel Blockers,
http://linkedlifedata.com/resource/pubmed/chemical/Calcium Channels,
http://linkedlifedata.com/resource/pubmed/chemical/Calcium-Transporting ATPases,
http://linkedlifedata.com/resource/pubmed/chemical/Enzyme Inhibitors,
http://linkedlifedata.com/resource/pubmed/chemical/Inositol 1,4,5-Trisphosphate...,
http://linkedlifedata.com/resource/pubmed/chemical/Peptides,
http://linkedlifedata.com/resource/pubmed/chemical/Receptors, Cytoplasmic and Nuclear,
http://linkedlifedata.com/resource/pubmed/chemical/Terpenes,
http://linkedlifedata.com/resource/pubmed/chemical/Thapsigargin,
http://linkedlifedata.com/resource/pubmed/chemical/Thimerosal,
http://linkedlifedata.com/resource/pubmed/chemical/omega-Conotoxin GVIA
|
| pubmed:status |
MEDLINE
|
| pubmed:month |
Mar
|
| pubmed:issn |
0143-4160
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| pubmed:author | |
| pubmed:issnType |
Print
|
| pubmed:volume |
19
|
| pubmed:owner |
NLM
|
| pubmed:authorsComplete |
Y
|
| pubmed:pagination |
219-27
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| pubmed:dateRevised |
2010-11-18
|
| pubmed:meshHeading |
pubmed-meshheading:8732262-Animals,
pubmed-meshheading:8732262-Calcium,
pubmed-meshheading:8732262-Calcium Channel Blockers,
pubmed-meshheading:8732262-Calcium Channels,
pubmed-meshheading:8732262-Calcium-Transporting ATPases,
pubmed-meshheading:8732262-Cell Nucleus,
pubmed-meshheading:8732262-Cytoplasm,
pubmed-meshheading:8732262-Enzyme Inhibitors,
pubmed-meshheading:8732262-Inositol 1,4,5-Trisphosphate Receptors,
pubmed-meshheading:8732262-Microscopy, Confocal,
pubmed-meshheading:8732262-Peptides,
pubmed-meshheading:8732262-Pituitary Gland,
pubmed-meshheading:8732262-Receptors, Cytoplasmic and Nuclear,
pubmed-meshheading:8732262-Signal Transduction,
pubmed-meshheading:8732262-Terpenes,
pubmed-meshheading:8732262-Thapsigargin,
pubmed-meshheading:8732262-Thimerosal,
pubmed-meshheading:8732262-Xenopus laevis,
pubmed-meshheading:8732262-omega-Conotoxin GVIA
|
| pubmed:year |
1996
|
| pubmed:articleTitle |
Spatial and temporal aspects of Ca2+ oscillations in Xenopus laevis melanotrope cells.
|
| pubmed:affiliation |
Department of Animal Physiology, Nijmegen Institute for Neurosciences, The Netherlands.
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| pubmed:publicationType |
Journal Article,
Research Support, Non-U.S. Gov't
|