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rdf:type |
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lifeskim:mentions |
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pubmed:dateCreated |
1992-6-26
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pubmed:abstractText |
1. The modulation by Ca2+ of the activation by inositol 1,4,5-trisphosphate (IP3) of Ca2+ channels present in native sarcoplasmic reticulum membranes from frog skeletal muscle was studied after channel incorporation into planar phospholipid bilayers in the presence of Ca2+ or Ba2+ as current carrier species. 2. Channel activity expressed as fractional open time (Po) was low (less than or equal to 0.15) in the presence of varying free Ca2+ concentrations bathing the myoplasmic face of the channel (cis side), and did not increase significantly between 0.01 and 30 microM-Ca2+. 3. Channel activation mediated by IP3 could be elicited from free Ca2+ levels similar to those of resting skeletal muscle (about 0.1 microM) and was found to be strongly regulated by the free Ca2+ concentration present at the myoplasmic moiety of the channel. 4. Channel activation by 10 microM-IP3 depended on the Ca2+ concentration on the cis side. Po reached a maximum between pCa 7.0 and 6.0, but decreased at higher concentrations of free Ca2+. Thus, Ca2+ exerted a modulatory influence on IP3-mediated activation in a concentration range where the channel was insensitive to Ca2+. 5. The results indicate that Ca2+ ions act as modulators of IP3 efficacy to open the channel. This could arise from an interaction of Ca2+ with the channel gating mechanism or with the agonist binding site.
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pubmed:grant |
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pubmed:commentsCorrections |
http://linkedlifedata.com/resource/pubmed/commentcorrection/1667801-1002681,
http://linkedlifedata.com/resource/pubmed/commentcorrection/1667801-2015378,
http://linkedlifedata.com/resource/pubmed/commentcorrection/1667801-2156262,
http://linkedlifedata.com/resource/pubmed/commentcorrection/1667801-2168221,
http://linkedlifedata.com/resource/pubmed/commentcorrection/1667801-2168425,
http://linkedlifedata.com/resource/pubmed/commentcorrection/1667801-2296584,
http://linkedlifedata.com/resource/pubmed/commentcorrection/1667801-2306208,
http://linkedlifedata.com/resource/pubmed/commentcorrection/1667801-2306496,
http://linkedlifedata.com/resource/pubmed/commentcorrection/1667801-2373998,
http://linkedlifedata.com/resource/pubmed/commentcorrection/1667801-2381765,
http://linkedlifedata.com/resource/pubmed/commentcorrection/1667801-2410794,
http://linkedlifedata.com/resource/pubmed/commentcorrection/1667801-2410798,
http://linkedlifedata.com/resource/pubmed/commentcorrection/1667801-2429317,
http://linkedlifedata.com/resource/pubmed/commentcorrection/1667801-2431098,
http://linkedlifedata.com/resource/pubmed/commentcorrection/1667801-2443015,
http://linkedlifedata.com/resource/pubmed/commentcorrection/1667801-2448775,
http://linkedlifedata.com/resource/pubmed/commentcorrection/1667801-2450090,
http://linkedlifedata.com/resource/pubmed/commentcorrection/1667801-2546932,
http://linkedlifedata.com/resource/pubmed/commentcorrection/1667801-2546933,
http://linkedlifedata.com/resource/pubmed/commentcorrection/1667801-2550825,
http://linkedlifedata.com/resource/pubmed/commentcorrection/1667801-2554991,
http://linkedlifedata.com/resource/pubmed/commentcorrection/1667801-2600080,
http://linkedlifedata.com/resource/pubmed/commentcorrection/1667801-2667466,
http://linkedlifedata.com/resource/pubmed/commentcorrection/1667801-2676352,
http://linkedlifedata.com/resource/pubmed/commentcorrection/1667801-2784673,
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http://linkedlifedata.com/resource/pubmed/commentcorrection/1667801-2849060,
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http://linkedlifedata.com/resource/pubmed/commentcorrection/1667801-2906144,
http://linkedlifedata.com/resource/pubmed/commentcorrection/1667801-2947569,
http://linkedlifedata.com/resource/pubmed/commentcorrection/1667801-3002474,
http://linkedlifedata.com/resource/pubmed/commentcorrection/1667801-3284380,
http://linkedlifedata.com/resource/pubmed/commentcorrection/1667801-3488368,
http://linkedlifedata.com/resource/pubmed/commentcorrection/1667801-3491073,
http://linkedlifedata.com/resource/pubmed/commentcorrection/1667801-3533912,
http://linkedlifedata.com/resource/pubmed/commentcorrection/1667801-3754147,
http://linkedlifedata.com/resource/pubmed/commentcorrection/1667801-3931630,
http://linkedlifedata.com/resource/pubmed/commentcorrection/1667801-6093162,
http://linkedlifedata.com/resource/pubmed/commentcorrection/1667801-6333869,
http://linkedlifedata.com/resource/pubmed/commentcorrection/1667801-6698971,
http://linkedlifedata.com/resource/pubmed/commentcorrection/1667801-7309698,
http://linkedlifedata.com/resource/pubmed/commentcorrection/1667801-7407109
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pubmed:language |
eng
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pubmed:journal |
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pubmed:citationSubset |
IM
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pubmed:chemical |
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pubmed:status |
MEDLINE
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pubmed:month |
Sep
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pubmed:issn |
0022-3751
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pubmed:author |
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pubmed:issnType |
Print
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pubmed:volume |
441
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pubmed:owner |
NLM
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pubmed:authorsComplete |
Y
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pubmed:pagination |
575-91
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pubmed:dateRevised |
2009-11-18
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pubmed:meshHeading |
pubmed-meshheading:1667801-Animals,
pubmed-meshheading:1667801-Anura,
pubmed-meshheading:1667801-Barium,
pubmed-meshheading:1667801-Binding Sites,
pubmed-meshheading:1667801-Calcium,
pubmed-meshheading:1667801-Calcium Channels,
pubmed-meshheading:1667801-Dose-Response Relationship, Drug,
pubmed-meshheading:1667801-Inositol 1,4,5-Trisphosphate,
pubmed-meshheading:1667801-Ion Channel Gating,
pubmed-meshheading:1667801-Kinetics,
pubmed-meshheading:1667801-Sarcoplasmic Reticulum
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pubmed:year |
1991
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pubmed:articleTitle |
Activation of inositol trisphosphate-sensitive Ca2+ channels of sarcoplasmic reticulum from frog skeletal muscle.
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pubmed:affiliation |
Departamento de Fisiología y Biofísica, Facultad de Medicina, Universidad de Chile.
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pubmed:publicationType |
Journal Article,
In Vitro,
Research Support, U.S. Gov't, P.H.S.,
Research Support, U.S. Gov't, Non-P.H.S.
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