Statements in which the resource exists as a subject.
PredicateObject
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.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Dec
pubmed:issn
0006-291X
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
pubmed:meshHeading
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