Source:http://linkedlifedata.com/resource/pubmed/id/10753879
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Predicate | Object |
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rdf:type | |
lifeskim:mentions | |
pubmed:issue |
15
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pubmed:dateCreated |
2000-5-5
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pubmed:abstractText |
Inositol phosphate (InsP) responses to receptor activation are assumed to involve phospholipase C cleavage of phosphatidylinositol 4,5-bisphosphate to generate Ins(1,4,5)P(3). However, in [(3)H]inositol-labeled rat neonatal cardiomyocytes (NCM) both initial and sustained [(3)H]InsP responses to alpha(1)-adrenergic receptor stimulation with norepinephrine (100 microM) were insensitive to the phosphatidylinositol 4,5-bisphosphate-binding agent neomycin (5 mM). Introduction of 300 microM unlabeled Ins(1,4, 5)P(3) into guanosine 5'-3-O-(thio)triphosphate (GTPgammaS)-stimulated, permeabilized [(3)H]inositol-labeled NCM increased [(3)H]Ins(1,4,5)P(3) slightly but did not significantly reduce levels of its metabolites [(3)H]Ins(1,4)P(2) and [(3)H]Ins(4)P, suggesting that these [(3)H]InsPs are not formed principally from [(3)H]Ins(1,4,5)P(3). In contrast, the calcium ionophore A23187 (10 microM) provoked [(3)H]InsP responses in intact NCM which were sensitive to neomycin, and elevation of free calcium in permeabilized NCM led to [(3)H]InsP responses characterized by marked increases in [(3)H]Ins(1,4,5)P(3) (2.9 +/- 0.2% of total [(3)H]InsPs after 20 min of high Ca(2+) treatment in comparison to 0. 21 +/- 0.05% of total [(3)H]InsPs accumulated after 20 min of GTPgammaS stimulation). These data provide evidence that Ins(1,4, 5)P(3) generation is not a major contributor to G protein-coupled InsP responses in NCM, but that substantial Ins(1,4,5)P(3) generation occurs under conditions of Ca(2+) overload. Thus in NCM, Ca(2+)-induced Ins(1,4,5)P(3) generation has the potential to worsen Ca(2+) overload and thereby aggravate Ca(2+)-induced electrophysiological perturbations.
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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/Calcimycin,
http://linkedlifedata.com/resource/pubmed/chemical/Calcium,
http://linkedlifedata.com/resource/pubmed/chemical/GTP-Binding Proteins,
http://linkedlifedata.com/resource/pubmed/chemical/Inositol 1,4,5-Trisphosphate,
http://linkedlifedata.com/resource/pubmed/chemical/Inositol Phosphates,
http://linkedlifedata.com/resource/pubmed/chemical/Neomycin,
http://linkedlifedata.com/resource/pubmed/chemical/Norepinephrine,
http://linkedlifedata.com/resource/pubmed/chemical/Type C Phospholipases
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pubmed:status |
MEDLINE
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pubmed:month |
Apr
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pubmed:issn |
0021-9258
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pubmed:author | |
pubmed:issnType |
Print
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pubmed:day |
14
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pubmed:volume |
275
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pubmed:owner |
NLM
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pubmed:authorsComplete |
Y
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pubmed:pagination |
10845-50
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pubmed:dateRevised |
2007-11-15
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pubmed:meshHeading |
pubmed-meshheading:10753879-Animals,
pubmed-meshheading:10753879-Animals, Newborn,
pubmed-meshheading:10753879-Calcimycin,
pubmed-meshheading:10753879-Calcium,
pubmed-meshheading:10753879-Cells, Cultured,
pubmed-meshheading:10753879-GTP-Binding Proteins,
pubmed-meshheading:10753879-Inositol 1,4,5-Trisphosphate,
pubmed-meshheading:10753879-Inositol Phosphates,
pubmed-meshheading:10753879-Myocardium,
pubmed-meshheading:10753879-Neomycin,
pubmed-meshheading:10753879-Norepinephrine,
pubmed-meshheading:10753879-Rats,
pubmed-meshheading:10753879-Rats, Sprague-Dawley,
pubmed-meshheading:10753879-Type C Phospholipases
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pubmed:year |
2000
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pubmed:articleTitle |
Ca(2+)-activated but not G protein-mediated inositol phosphate responses in rat neonatal cardiomyocytes involve inositol 1,4, 5-trisphosphate generation.
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pubmed:affiliation |
Cellular Biochemistry Laboratory, Baker Medical Research Institute, Melbourne 8008, Victoria, Australia.
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pubmed:publicationType |
Journal Article
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