Linked Life Data

11071898

Source:http://linkedlifedata.com/resource/pubmed/id/11071898

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
6
pubmed:dateCreated
2001-5-23
pubmed:abstractText
Liver cells respond to changes in Ca(2+)(o). The hepatic functions affected include bile secretion, metabolic activity, liver regeneration, and the response to xenobiotics. In the present study, we demonstrate the presence, in the liver, of the extracellular calcium-sensing receptor (CASR), described previously in the parathyroid and thyroid glands and kidney. CASR mRNA was specifically expressed in hepatocytes and was absent in nonparenchymal liver cells (stellate, endothelial, and Kupffer cells). Western blot analysis using a specific CASR antibody showed staining in both whole liver and hepatocyte extracts. Immunohistochemistry and in situ hybridization of rat liver sections showed expression of CASR protein and mRNA by a subset of hepatocytes. The known agonists of the CASR, gadolinium (Gd(3+); 0.5-3.0 mm) and spermine (1.25-20 mm), in the absence of Ca(2+)(o), elicited dose-related increases in Ca(2+)(i) in isolated rat hepatocytes loaded with Fura-2/acetoxymethyl ester. There was a greatly attenuated response to a second challenge with either agonist. The response was also abrogated when inositol 1,4,5-trisphosphate (IP(3))-sensitive calcium pools had been depleted by pretreatment with either thapsigargin or phenylephrine, an alpha(1)-adrenergic receptor agonist known to mobilize Ca(2+)(i) from IP(3)-sensitive pools. Addition of the deschloro-phenylalkylamine compound, NPS R-467, but not the S enantiomer, NPS S-467, increased the sensitivity of the Ca(2+)(i) mobilization response to 1.25 mm spermine. Bile flow ceased after Ca(2+)(o) withdrawal, and its recovery was enhanced by spermine in isolated perfused liver preparations. The CASR agonists Ca(2+) and Gd(3+) increased bile flow, and the response to a submaximal Ca(2+) concentration was enhanced by NPS R-467 but not the S compound. Thus, the data indicate that rat hepatocytes harbor a CASR capable of mobilizing Ca(2+)(i) from IP(3)-sensitive stores and that activation of the CASR stimulates bile flow.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Feb
pubmed:issn
0021-9258
pubmed:author
pubmed:issnType
Print
pubmed:day
9
pubmed:volume
276
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
4070-9
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed-meshheading:11071898-Aniline Compounds, pubmed-meshheading:11071898-Animals, pubmed-meshheading:11071898-Base Sequence, pubmed-meshheading:11071898-Bile, pubmed-meshheading:11071898-Calcium, pubmed-meshheading:11071898-Cell Line, pubmed-meshheading:11071898-DNA Primers, pubmed-meshheading:11071898-Extracellular Space, pubmed-meshheading:11071898-Female, pubmed-meshheading:11071898-Hepatocytes, pubmed-meshheading:11071898-In Situ Hybridization, pubmed-meshheading:11071898-Inositol 1,4,5-Trisphosphate, pubmed-meshheading:11071898-Mice, pubmed-meshheading:11071898-RNA, Messenger, pubmed-meshheading:11071898-Rats, pubmed-meshheading:11071898-Rats, Sprague-Dawley, pubmed-meshheading:11071898-Receptors, Calcium-Sensing, pubmed-meshheading:11071898-Receptors, Cell Surface, pubmed-meshheading:11071898-Reverse Transcriptase Polymerase Chain Reaction, pubmed-meshheading:11071898-Spermine
pubmed:year
2001
pubmed:articleTitle
Extracellular calcium-sensing receptor is expressed in rat hepatocytes. coupling to intracellular calcium mobilization and stimulation of bile flow.
pubmed:affiliation
Departments of Medicine, Physiology and Human Genetics, McGill University and Royal Victoria Hospital, Montreal, Quebec H3A 1A1, Canada.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't