rdf:type |
|
lifeskim:mentions |
|
pubmed:issue |
2
|
pubmed:dateCreated |
2003-11-25
|
pubmed:abstractText |
Active Ca(2+) absorption through epithelial Ca(2+) channels TRPV5/6 in duodenum is activated by hyperpolarisation. However, when diet and Ca(2+) are plentiful, digestion products cause depolarisation. We therefore used homology-based PCR from a rat jejunal mucosal cDNA preparation to reveal the presence of the neuroendocrine L-type isoform Ca(v)1.3alpha(1). Immunocytochemical labelling and immunoblotting localised Ca(v)1.3 alpha(1) protein in apical membrane from proximal jejunum to mid ileum. Perfusion studies in vivo with 1.25 mM luminal Ca(2+) revealed L-type channel activity. Inhibition of glucose absorption with phloridzin strongly inhibited 45Ca(2+) absorption; absorption was inhibited by nifedipine and Mg(2+) and activated by Bay K 8644, none of which affect TRPV5/6. At 10mM Ca(2+), nifedipine inhibited 45Ca(2+) absorption with a time course similar to that at 1.25 mM Ca(2+): absorption was therefore channel-mediated rather than paracellular. We suggest that in times of dietary sufficiency, Ca(v)1.3 may mediate a significant route of Ca(2+) absorption into the body.
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pubmed:language |
eng
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pubmed:journal |
|
pubmed:citationSubset |
IM
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pubmed:chemical |
|
pubmed:status |
MEDLINE
|
pubmed:month |
Dec
|
pubmed:issn |
0006-291X
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pubmed:author |
|
pubmed:issnType |
Print
|
pubmed:day |
12
|
pubmed:volume |
312
|
pubmed:owner |
NLM
|
pubmed:authorsComplete |
Y
|
pubmed:pagination |
487-93
|
pubmed:dateRevised |
2006-11-15
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pubmed:meshHeading |
pubmed-meshheading:14637163-3-Pyridinecarboxylic acid...,
pubmed-meshheading:14637163-Absorption,
pubmed-meshheading:14637163-Animals,
pubmed-meshheading:14637163-Calcium,
pubmed-meshheading:14637163-Calcium Channels,
pubmed-meshheading:14637163-Calcium Channels, L-Type,
pubmed-meshheading:14637163-Culture Techniques,
pubmed-meshheading:14637163-Intestinal Mucosa,
pubmed-meshheading:14637163-Intestines,
pubmed-meshheading:14637163-Ion Channel Gating,
pubmed-meshheading:14637163-Jejunum,
pubmed-meshheading:14637163-Magnesium,
pubmed-meshheading:14637163-Male,
pubmed-meshheading:14637163-Nifedipine,
pubmed-meshheading:14637163-Phlorhizin,
pubmed-meshheading:14637163-Rats,
pubmed-meshheading:14637163-Rats, Wistar
|
pubmed:year |
2003
|
pubmed:articleTitle |
A role for Ca(v)1.3 in rat intestinal calcium absorption.
|
pubmed:affiliation |
Department of Biology (Area 3), University of York, York YO10 5YW, UK.
|
pubmed:publicationType |
Journal Article,
Research Support, Non-U.S. Gov't
|