Document Detail


Failure of endothelin-1 to activate store-operated Ca2+ channels by lack of mobilization from intracellular Ca2+ stores in cultured bovine adrenal chromaffin cells.
MedLine Citation:
PMID:  11485037     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
We have recently shown that in addition to L-type voltage-operated Ca2+ channel (VOC), endothelin-1 (ET-1) stimulation opens two types of Ca2+-permeable nonselective cation channels [designated nonselective cation channel-1 (NSCC-1) and NSCC-2]. However, in this Ca2+ entry, the involvement of store-operated Ca2+ channel (SOCC), which is suggested to exist in chromaffin cells, was unclear. Those NSCCs as well as SOCC can be pharmacologically discriminated using Ca2+ channel blockers such as SK&F 96365 and LOE 908. To clarify whether SOCC should actually exist and play a role in Ca2+ entry in chromaffin cells stimulated with ET-1, we examined the effects of removal of extracellular Ca2+, thapsigargin (TG, an inhibitor of endoplasmic reticulum Ca2+-ATPase), LOE 908 and SK&F 96365 on cytosolic free Ca2+ concentrations ([Ca2+]i) in cultured bovine adrenal chromaffin cells. After the cells were exposed to Ca2+-free medium followed by exposure to TG to deplete Ca2+ from the intracellular Ca2+ store, restoration of extracellular Ca2+ caused a gradual increase in [Ca2+]i (to about 200% of control). The increase was unaffected by LOE 908, but completely abolished by SK&F 96365. In the Ca2+-free medium, no increase in [Ca2+]i by ET-1 was observed, but the subsequent restoration of extracellular Ca2+ induced a rapid increase in [Ca2+]i (to the same level of [Ca2+]i as that evoked by ET-1 in the normal medium (1.0 mM Ca2+)). Since SK&F 96365 is also a blocker of SOCC, these results indicate that in bovine adrenal chromaffin cells, Ca2+ entry through SOCC (Ca2+ influx through the capacitative Ca2+ entry system) occurs but is comparably weak, and that it virtually does not work on the stimulation of ET-1.
Authors:
K Lee; H Morita; Y Iwamuro; X F Zhang; Y Okamoto; S Miwa
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Naunyn-Schmiedeberg's archives of pharmacology     Volume:  364     ISSN:  0028-1298     ISO Abbreviation:  Naunyn Schmiedebergs Arch. Pharmacol.     Publication Date:  2001 Jul 
Date Detail:
Created Date:  2001-08-03     Completed Date:  2002-03-28     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  0326264     Medline TA:  Naunyn Schmiedebergs Arch Pharmacol     Country:  Germany    
Other Details:
Languages:  eng     Pagination:  42-6     Citation Subset:  IM    
Affiliation:
Department of Physiology, Gifu University School of Medicine, Japan. kl@cc.gifu-u.ac.jp
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MeSH Terms
Descriptor/Qualifier:
Acetamides / pharmacology
Animals
Calcium / metabolism*
Calcium Channel Blockers / pharmacology
Calcium Channels, L-Type / metabolism*
Cattle
Cells, Cultured
Chromaffin Cells / metabolism*
Endothelin-1 / physiology*
Enzyme Inhibitors / pharmacology
Imidazoles / pharmacology*
Ion Channels / drug effects
Isoquinolines / pharmacology
Thapsigargin / pharmacology
Chemical
Reg. No./Substance:
0/Acetamides; 0/Calcium Channel Blockers; 0/Calcium Channels, L-Type; 0/Endothelin-1; 0/Enzyme Inhibitors; 0/Imidazoles; 0/Ion Channels; 0/Isoquinolines; 130495-35-1/1-(2-(3-(4-methoxyphenyl)propoxy)-4-methoxyphenylethyl)-1H-imidazole; 149759-26-2/LOE 908; 67526-95-8/Thapsigargin; 7440-70-2/Calcium

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


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