Document Detail


Induction of cholestasis in the perfused rat liver by 2-aminoethyl diphenylborate, an inhibitor of the hepatocyte plasma membrane Ca2+ channels.
MedLine Citation:
PMID:  15377289     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
BACKGROUND AND AIMS: An increase in the cytoplasmic free Ca2+ concentration in hepatocytes as a result of the release of Ca2+ from intracellular stores and Ca2+ inflow from the extracellular space is a necessary part of the mechanism by which bile acids are moved along the bile cannaliculus by contraction of the cannaliculus. 2-Aminoethyl diphenylborate (2-APB) is a recently discovered inhibitor of store-operated plasma membrane Ca2+ channels in hepatocytes. The aim of the present study was to test the ability of 2-APB to inhibit bile flow. METHODS: Bile flow was measured in the isolated perfused rat liver using cannulation of the common bile duct. Measurements were carried out in the presence or absence of 2-APB in either the presence of taurocholic acid (to enhance basal bile flow) or in the absence of taurocholic acid and in the presence of the hormones vasopressin and glucagon, which are known to stimulate bile flow. RESULTS: In livers perfused in the presence of taurocholic acid, 2-APB reversibly inhibited bile flow with a slow time of onset. The time of onset of inhibition was reduced by prior addition of the endoplasmic reticulum (Ca(2+) + Mg2+)adenosine triphosphatase inhibitor, 2,5-di-t-butylhydroquinone. In livers perfused in the absence of taurocholate, 2-APB had little effect on the basal rate of bile flow, but inhibited the ability of vasopressin and glucagon to stimulate bile flow. CONCLUSIONS: It is concluded that an inhibitor of hepatocyte plasma membrane Ca2+ channels can induce cholestasis. The results provide evidence that suggests that, over a period of time, the normal function of hepatocyte store-operated Ca2+ channels is required to maintain bile flow. Future strategies directed at the regulation of bile flow might include pharmacological or other interventions that modulate Ca2+ inflow to hepatocytes.
Authors:
Roland B Gregory; Rachael Hughes; Gregory J Barritt
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Journal of gastroenterology and hepatology     Volume:  19     ISSN:  0815-9319     ISO Abbreviation:  J. Gastroenterol. Hepatol.     Publication Date:  2004 Oct 
Date Detail:
Created Date:  2004-09-20     Completed Date:  2005-03-31     Revised Date:  2010-03-24    
Medline Journal Info:
Nlm Unique ID:  8607909     Medline TA:  J Gastroenterol Hepatol     Country:  Australia    
Other Details:
Languages:  eng     Pagination:  1128-34     Citation Subset:  IM    
Affiliation:
Department of Medical Biochemistry, School of Medicine, Faculty of Health Sciences, Flinders University, Adelaide, South Australia, Australia.
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MeSH Terms
Descriptor/Qualifier:
Animals
Bile / drug effects*,  physiology
Boron Compounds / adverse effects*
Calcium Channel Blockers / adverse effects*
Calcium Channels / drug effects
Calcium-Transporting ATPases / drug effects
Cholestasis / chemically induced*,  metabolism
Enzyme Inhibitors / pharmacology
Glucagon / pharmacology
Hepatocytes / metabolism*
Hydroquinones / pharmacology
Liver / metabolism
Peptide Hormones / pharmacology
Rats
Taurocholic Acid / pharmacology
Vasopressins / pharmacology
Chemical
Reg. No./Substance:
0/2-aminoethoxydiphenyl borate; 0/Boron Compounds; 0/Calcium Channel Blockers; 0/Calcium Channels; 0/Enzyme Inhibitors; 0/Hydroquinones; 0/Peptide Hormones; 11000-17-2/Vasopressins; 81-24-3/Taurocholic Acid; 88-58-4/2,5-di-tert-butylhydroquinone; 9007-92-5/Glucagon; EC 3.6.1.8/Calcium-Transporting ATPases

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


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