Source:http://linkedlifedata.com/resource/pubmed/id/17572852
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| Predicate | Object |
|---|---|
| rdf:type | |
| lifeskim:mentions | |
| pubmed:issue |
2-3
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| pubmed:dateCreated |
2007-9-19
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| pubmed:abstractText |
Purkinje (P)-fibres are cardiac myocytes that are specialized for fast conduction of the electrical signal. P-fibres are usually defined as having the following identifying features: lack of T tubules; frequent lateral cell junctions; deep indentations at the intercalated discs level; the CX40 isoforms of gap junction proteins and, in large mammals, paucity of myofibrils and abundance of glycogen. We have examined the ultrastructure of P-fibres in free running P-strands from right and left ventricles of small (mouse and rat) intermediate (rabbit) and large (dog) size mammals focusing on presence and distribution of the T tubules. In contrast with previous studies, we find that P-fibres do have T tubules which form normal dyadic associations with the sarcoplasmic reticulum and that the frequency of tubules varies with the size of the animal. Profiles of T tubules and dyads are present over short segments of individual P-cells flanked by totally T tubule-free segments. It is thought that lack of T tubules in P-cells is necessary to reduce capacitance and thus accelerate action potential spread. This may not be as important in a small heart.
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| pubmed:grant | |
| pubmed:language |
eng
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| pubmed:journal | |
| pubmed:citationSubset |
IM
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| pubmed:status |
MEDLINE
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| pubmed:issn |
0142-4319
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| pubmed:author | |
| pubmed:issnType |
Print
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| pubmed:volume |
28
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| pubmed:owner |
NLM
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| pubmed:authorsComplete |
Y
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| pubmed:pagination |
115-21
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| pubmed:meshHeading |
pubmed-meshheading:17572852-Action Potentials,
pubmed-meshheading:17572852-Animals,
pubmed-meshheading:17572852-Body Size,
pubmed-meshheading:17572852-Calcium Signaling,
pubmed-meshheading:17572852-Cell Communication,
pubmed-meshheading:17572852-Dogs,
pubmed-meshheading:17572852-Gap Junctions,
pubmed-meshheading:17572852-Heart Ventricles,
pubmed-meshheading:17572852-Intercellular Junctions,
pubmed-meshheading:17572852-Mice,
pubmed-meshheading:17572852-Microscopy, Electron, Transmission,
pubmed-meshheading:17572852-Microtubules,
pubmed-meshheading:17572852-Muscle Contraction,
pubmed-meshheading:17572852-Myocardial Contraction,
pubmed-meshheading:17572852-Myocardium,
pubmed-meshheading:17572852-Myocytes, Cardiac,
pubmed-meshheading:17572852-Purkinje Fibers,
pubmed-meshheading:17572852-Rabbits,
pubmed-meshheading:17572852-Rats,
pubmed-meshheading:17572852-Sarcoplasmic Reticulum,
pubmed-meshheading:17572852-Species Specificity
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| pubmed:year |
2007
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| pubmed:articleTitle |
T-tubule profiles in Purkinje fibres of mammalian myocardium.
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| pubmed:affiliation |
Department of Cell & Developmental Biology, University of Pennsylvania, School of Medicine, Anat/Chem Building, Philadelphia, PA 19104-6058, USA. dimaio@mail.med.upenn.edu
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| pubmed:publicationType |
Journal Article,
Research Support, N.I.H., Extramural
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