Document Detail


Potentiation by Ca2+ ionophores and inhibition by extracellular KCl of endothelin-induced phosphoinositide turnover in C6 glioma cells.
MedLine Citation:
PMID:  1338900     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
Interactions between endothelin-1 (ET)-induced phosphoinositide (PI) hydrolysis and agents that increase Ca2+ influx (i.e. A23187 and ionomycin) or induce depolarization (i.e. KCl) were investigated using C6 glioma. A23187 dose-dependently potentiated ET (30 nM)- and ATP (100 microM)-induced [3H]inositol phosphate (IP) accumulation. This potentiation was associated with an increase in the maximal stimulation elicited by both ET and ATP but their EC50 values were unchanged. This effect of A23187 occurred at concentrations that did not affect basal PI turnover; i.e. 10 nM-3 microM. Ionomycin within the range of 1 nM-1 microM also significantly enhanced ET-induced PI breakdown and this effect was associated with an increase of [Ca2+]i. KCl in a concentration-dependent manner (14.7-54.7 mM) markedly inhibited PI breakdown elicited by ET and ATP, but had much less inhibition on basal activity and no effect on A23187- and ionomycin-induced responses. In parallel, KCl added before or after ET, sharply attenuated the increase of ET-induced [Ca2+]i but did not affect basal level or ionomycin-induced [Ca2+]i response. Neither the potentiation by A23187 nor the inhibition by KCl of ET-induced PI turnover was observed in cultured cerebellar astrocytes. Our results suggest that the cell type-specific regulation by Ca2+ ionophores and KCl on ET-induced PI metabolism is closely related to perturbation of [Ca2+]i.
Authors:
W W Lin; D M Chuang
Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Neurochemistry international     Volume:  21     ISSN:  0197-0186     ISO Abbreviation:  Neurochem. Int.     Publication Date:  1992 Sep 
Date Detail:
Created Date:  1993-06-24     Completed Date:  1993-06-24     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  8006959     Medline TA:  Neurochem Int     Country:  ENGLAND    
Other Details:
Languages:  eng     Pagination:  293-301     Citation Subset:  IM    
Affiliation:
Section on Molecular Neurobiology, National Institute of Mental Health, Bethesda, MD 20892.
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MeSH Terms
Descriptor/Qualifier:
Adenosine Diphosphate / pharmacology
Adenosine Triphosphate / pharmacology
Animals
Calcimycin / pharmacology*
Calcium / metabolism*
Dose-Response Relationship, Drug
Endothelins / pharmacology*
Glioma / metabolism*
Inositol / metabolism
Inositol Phosphates / metabolism*
Ionomycin / pharmacology*
Kinetics
Phosphatidylinositols / metabolism*
Potassium Chloride / pharmacology*
Time Factors
Tumor Cells, Cultured
Chemical
Reg. No./Substance:
0/Endothelins; 0/Inositol Phosphates; 0/Phosphatidylinositols; 52665-69-7/Calcimycin; 56-65-5/Adenosine Triphosphate; 56092-81-0/Ionomycin; 58-64-0/Adenosine Diphosphate; 6917-35-7/Inositol; 7440-70-2/Calcium; 7447-40-7/Potassium Chloride

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


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