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Predicate | Object |
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rdf:type | |
lifeskim:mentions | |
pubmed:issue |
1
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pubmed:dateCreated |
1994-7-5
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pubmed:abstractText |
The quenching of fura-2 fluorescence by the influx of extracellular Mn2+ was measured to indicate the flux rates through receptor-operated calcium channels in the plasma membrane of rat hepatocytes. Neomycin, an inhibitor of phospholipase C, inhibited the vasopressin-induced influx of Mn2+. Thus, the agonist-induced entry of extracellular calcium into hepatocytes is linked to a phospholipase C-generated second messenger. Microinjection of inositol 1,3,4,5-tetrakisphosphate [Ins(1,3,4,5)P4], inositol 1,4,5-trisphosphate [Ins(1,4,5)P3] or 3-deoxy-3-fluoro-Ins(1,4,5)P3 revealed that Ins(1,4,5)P3 rather than Ins(1,3,4,5)P4 is responsible for calcium entry. The activation of phospholipase C by vasopressin produced an influx of Mn2+ independent of the depletion of intracellular calcium stores if this depletion was delayed by the Ins(1,4,5)P3 receptor antagonist heparin or by the use of a low agonist concentration. Thapsigargin, an inhibitor of the store calcium pump, leading to an Ins(1,4,5)P3-independent emptying of stores, gave a short living signal (less than 3 min) for calcium entry. We propose that Ins(1,4,5)P3 is able to stimulate calcium entry by two pathways. (a) Ins(1,4,5)P3 activates receptor-operated calcium channels in a direct manner. The calcium entry resulting from this is followed (b) by the Ins(1,4,5)P3-induced depletion of calcium stores, producing a store-dependent entry.
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pubmed:language |
eng
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pubmed:journal | |
pubmed:citationSubset |
IM
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pubmed:chemical |
http://linkedlifedata.com/resource/pubmed/chemical/Calcium,
http://linkedlifedata.com/resource/pubmed/chemical/Calcium Channels,
http://linkedlifedata.com/resource/pubmed/chemical/Inositol 1,4,5-Trisphosphate,
http://linkedlifedata.com/resource/pubmed/chemical/Inositol 1,4,5-Trisphosphate...,
http://linkedlifedata.com/resource/pubmed/chemical/Manganese,
http://linkedlifedata.com/resource/pubmed/chemical/Receptors, Cytoplasmic and Nuclear
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pubmed:status |
MEDLINE
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pubmed:month |
May
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pubmed:issn |
0014-2956
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pubmed:author | |
pubmed:issnType |
Print
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pubmed:day |
15
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pubmed:volume |
222
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pubmed:owner |
NLM
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pubmed:authorsComplete |
Y
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pubmed:pagination |
229-34
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pubmed:dateRevised |
2007-7-23
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pubmed:meshHeading |
pubmed-meshheading:8200348-Animals,
pubmed-meshheading:8200348-Calcium,
pubmed-meshheading:8200348-Calcium Channels,
pubmed-meshheading:8200348-Inositol 1,4,5-Trisphosphate,
pubmed-meshheading:8200348-Inositol 1,4,5-Trisphosphate Receptors,
pubmed-meshheading:8200348-Ion Transport,
pubmed-meshheading:8200348-Liver,
pubmed-meshheading:8200348-Male,
pubmed-meshheading:8200348-Manganese,
pubmed-meshheading:8200348-Rats,
pubmed-meshheading:8200348-Rats, Wistar,
pubmed-meshheading:8200348-Receptors, Cytoplasmic and Nuclear
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pubmed:year |
1994
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pubmed:articleTitle |
Inositol 1,4,5-trisphosphate activates receptor-mediated calcium entry by two different pathways in hepatocytes.
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pubmed:affiliation |
Institute of Biochemistry, Otto-von-Guericke-University Magdeburg, Germany.
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pubmed:publicationType |
Journal Article
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