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J Biol Chem, Vol. 275, Issue 18, 13411-13414, May 5, 2000
From INSERM U442, Université Paris-Sud, Bât. 443, 91405 Orsay, France
Store-operated Ca2+ entry was
investigated by monitoring the Ca2+-dependent
K+ permeability in voltage-clamped guinea pig hepatocytes.
In physiological conditions, intracellular Ca2+ stores are
discharged following agonist stimulation, but depletion of this stores
can be achieved using Ca2+-Mg2+-ATPase
inhibitors such as 2,5-di(tert-butyl)-1,4-benzohydroquinone and thapsigargin. The effect of internal Ca2+ store
depletion on Ca2+ influx was tested in single cells using
inositol 1,4,5-trisphosphate (InsP3) release from caged
InsP3 after treatment of the cells with
2,5-di(tert-butyl)-1,4-benzohydroquinone or thapsigargin in
Ca2+-free solutions. We show that the photolytic release of
1-D-myo-inositol 1,4-bisphosphate
5-phosphorothioate, a stable analog of InsP3, and
Ca2+ store depletion have additive effects to activate a
high level of Ca2+ entry in single guinea pig hepatocytes.
These results suggest that there is a direct functional interaction
between InsP3 receptors and Ca2+ channels in
the plasma membrane, although the nature of these Ca2+
channels in hepatocytes is unclear.
Supported by a Singer-Polignac sponsorship. Present
address: INSERM U533, Hôtel-Dieu, 44000 Nantes, France.
§
Present address: EA 2674, Université de Nice-Sophia
Antipolis, Faculté des sciences, Parc Valrose, 06108 Nice, France.
¶
To whom correspondence and reprint requests should be
addressed. Tel.: 33-169156865; Fax: 33-169155893; E-mail:
thierry.capiod@ibaic.u-psud.fr.
Copyright © 2000 by The American Society for Biochemistry and Molecular Biology, Inc. This article has been cited by other articles:
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