Document Detail

Modulation of intercellular calcium signaling in astrocytes by extracellular calcium and magnesium.
MedLine Citation:
PMID:  12898705     Owner:  NLM     Status:  MEDLINE    
The extracellular concentrations of Ca(2+) and Mg(2+) are well known to play important roles in the function of the central nervous system. We examined the effects of extracellular Ca(2+) and Mg(2+) on ATP release and intercellular signaling in astrocytes. The extent of propagation of intercellular Ca(2+) waves evoked by mechanical stimulation was increased by reduction of extracellular Ca(2+) ([Ca(2+)](o)) or Mg(2+) concentration ([Mg(2+)](o)) and was decreased by elevated [Mg(2+)](o). Reduction of extracellular Ca(2+) concentration ([Ca(2+)](o)) evokes intercellular Ca(2+) signaling in astrocytes; a similar effect was observed in response to change from 5 mM [Mg(2+)](o) to 0 [Mg(2+)](o). Release of low-molecular-weight dyes and ATP was also activated by low [Ca(2+)](o) or [Mg(2+)](o) and inhibited by high [Ca(2+)](o) or [Mg(2+)](o). Astrocytes showed low [Ca(2+)](o)-activated whole cell currents consistent with currents through connexin hemichannels. These currents were inhibited by extracellular Mg(2+). We conclude that extracellular divalent cations modulate intercellular Ca(2+) signaling in astrocytes by modulating the release of ATP, possibly via connexin hemichannels.
Charles Stout; Andrew Charles
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Publication Detail:
Type:  Journal Article; Research Support, U.S. Gov't, P.H.S.    
Journal Detail:
Title:  Glia     Volume:  43     ISSN:  0894-1491     ISO Abbreviation:  Glia     Publication Date:  2003 Sep 
Date Detail:
Created Date:  2003-08-04     Completed Date:  2003-12-12     Revised Date:  2007-11-14    
Medline Journal Info:
Nlm Unique ID:  8806785     Medline TA:  Glia     Country:  United States    
Other Details:
Languages:  eng     Pagination:  265-73     Citation Subset:  IM    
Copyright Information:
Copyright 2003 Wiley-Liss, Inc.
Loma Linda University School of Medicine, Loma Linda, California, USA.
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MeSH Terms
Adenosine Triphosphate / metabolism
Animals, Newborn
Astrocytes / drug effects,  metabolism*
Calcium / deficiency*,  pharmacology
Calcium Signaling / drug effects,  physiology*
Cells, Cultured
Central Nervous System / cytology,  metabolism*
Coloring Agents / diagnostic use
Connexins / metabolism
Extracellular Fluid / drug effects,  metabolism
Gap Junctions / drug effects,  metabolism
Intracellular Fluid / drug effects,  metabolism
Magnesium / metabolism*,  pharmacology
Magnesium Deficiency / metabolism
Membrane Potentials / physiology
Physical Stimulation
Up-Regulation / drug effects,  physiology
Grant Support
Reg. No./Substance:
0/Coloring Agents; 0/Connexins; 56-65-5/Adenosine Triphosphate; 7439-95-4/Magnesium; 7440-70-2/Calcium

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