Source:http://linkedlifedata.com/resource/pubmed/id/15662034
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| Predicate | Object |
|---|---|
| rdf:type | |
| lifeskim:mentions | |
| pubmed:issue |
4
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| pubmed:dateCreated |
2005-3-4
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| pubmed:abstractText |
Action potential duration (APD) restitution properties and repolarization alternans are thought to be important arrhythmogenic factors. We investigated the role of intracellular calcium (Ca2+i) cycling in regulating APD restitution slope and repolarization (APD) alternans in patch-clamped rabbit ventricular myocytes at 34 to 36 degrees C, using the perforated or ruptured patch clamp techniques with Fura-2-AM to record Ca2+i. When APD restitution was measured by either the standard extrastimulus (S1S2) method or the dynamic rapid pacing method, the maximum APD restitution slope exceeded 1 by both methods, but was more shallow with the dynamic method. These differences were associated with greater Ca2+i accumulation during dynamic pacing. The onset of APD alternans occurred at diastolic intervals at which the APD restitution slope was significantly <1 and was abolished by suppressing sarcoplasmic reticulum (SR) Ca2+i cycling with thapsigargin and ryanodine, or buffering the global Ca2+i transient with BAPTA-AM or BAPTA. Thapsigargin and ryanodine flattened APD restitution slope to <1 when measured by the dynamic method, but not by the S1S2 method. BAPTA-AM or BAPTA failed to flatten APD restitution slope to <1 by either method. In conclusion, APD alternans requires intact Ca2+i cycling and is not reliably predicted by APD restitution slope when Ca2+i cycling is suppressed. Ca2+i cycling may contribute to differences between APD restitution curves measured by S1S2 versus dynamic pacing protocols by inducing short-term memory effects related to pacing-dependent Ca2+i accumulation.
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| pubmed:grant | |
| pubmed:commentsCorrections | |
| pubmed:language |
eng
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| pubmed:journal | |
| pubmed:citationSubset |
IM
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| pubmed:chemical |
http://linkedlifedata.com/resource/pubmed/chemical/1,2-bis(2-aminophenoxy)ethane...,
http://linkedlifedata.com/resource/pubmed/chemical/Caffeine,
http://linkedlifedata.com/resource/pubmed/chemical/Calcium,
http://linkedlifedata.com/resource/pubmed/chemical/Calcium Channels,
http://linkedlifedata.com/resource/pubmed/chemical/Calcium Channels, L-Type,
http://linkedlifedata.com/resource/pubmed/chemical/Egtazic Acid,
http://linkedlifedata.com/resource/pubmed/chemical/Ryanodine,
http://linkedlifedata.com/resource/pubmed/chemical/Thapsigargin
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| pubmed:status |
MEDLINE
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| pubmed:month |
Mar
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| pubmed:issn |
1524-4571
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| pubmed:author | |
| pubmed:issnType |
Electronic
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| pubmed:day |
4
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| pubmed:volume |
96
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| pubmed:owner |
NLM
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| pubmed:authorsComplete |
Y
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| pubmed:pagination |
459-66
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| pubmed:dateRevised |
2007-11-14
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| pubmed:meshHeading |
pubmed-meshheading:15662034-Action Potentials,
pubmed-meshheading:15662034-Animals,
pubmed-meshheading:15662034-Caffeine,
pubmed-meshheading:15662034-Calcium,
pubmed-meshheading:15662034-Calcium Channels,
pubmed-meshheading:15662034-Calcium Channels, L-Type,
pubmed-meshheading:15662034-Calcium Signaling,
pubmed-meshheading:15662034-Cardiac Pacing, Artificial,
pubmed-meshheading:15662034-Cells, Cultured,
pubmed-meshheading:15662034-Egtazic Acid,
pubmed-meshheading:15662034-Heart Conduction System,
pubmed-meshheading:15662034-Humans,
pubmed-meshheading:15662034-Ion Transport,
pubmed-meshheading:15662034-Models, Cardiovascular,
pubmed-meshheading:15662034-Myocardium,
pubmed-meshheading:15662034-Myocytes, Cardiac,
pubmed-meshheading:15662034-Patch-Clamp Techniques,
pubmed-meshheading:15662034-Rabbits,
pubmed-meshheading:15662034-Ryanodine,
pubmed-meshheading:15662034-Sarcoplasmic Reticulum,
pubmed-meshheading:15662034-Tachycardia, Ventricular,
pubmed-meshheading:15662034-Thapsigargin,
pubmed-meshheading:15662034-Time Factors
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| pubmed:year |
2005
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| pubmed:articleTitle |
Action potential duration restitution and alternans in rabbit ventricular myocytes: the key role of intracellular calcium cycling.
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| pubmed:affiliation |
UCLA Cardiovascular Research Laboratory, Department of Medicine (Cardiology), David Geffen School of Medicine at UCLA, Los Angeles, Calif 90095-1679, USA. jgoldhaber@mednet.ucla.edu
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| pubmed:publicationType |
Journal Article,
Research Support, U.S. Gov't, P.H.S.,
Research Support, Non-U.S. Gov't,
Research Support, N.I.H., Extramural
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