-transparent.png){kind=logo}
Inositol 1,4,5-trisphosphate (IP3) induced Ca2+ release in digitonin permeabilized rat pancreatic acinar cells is specifically inhibited by decavanadate. The Ca2+ release induced with 0.18 microM IP3 is half maximally inhibited with approximately 5 microM decavanadate. Complete inhibition is achieved with around 20 microM decavanadate. Removal of decavanadate from the permeabilized cells fully restores sensitivity towards IP3, indicating the reversibility of the inhibition. Oligovanadate, which inhibits ATP dependent Ca2+ uptake into intracellular stores, does not influence IP3 induced Ca2+ release. In order to reveal the mechanism underlying the effects of the different vanadate species, binding of IP3 to the same cellular preparations was investigated. We found that binding of IP3 to a high affinity receptor site (Kd approx. 1.2 nM) could be abolished by decavanadate but not by oligovanadate. With 0.5 microM decavanadate, IP3 binding was half maximally inhibited. A similar potency of decavanadate was also found with adrenal cortex microsomes which bind IP3 with the same affinity (Kd approx. 1.4 nM) as permeabilized pancreatic acinar cells. Labelled IP3 was displaced from these subcellular membranes with similar kinetics by unlabelled IP3 and decavanadate. The data suggest that the inhibitory action of decavanadate on IP3 induced Ca2+ release is a consequence of its effect on binding of IP3 to its receptor.
K J Föhr, and
Y Wahl, and
R Engling, and
T P Kemmer, and
M Gratzl
February 1990,
The Biochemical journal,
K J Föhr, and
Y Wahl, and
R Engling, and
T P Kemmer, and
M Gratzl
February 1986,
Biochemical and biophysical research communications,
K J Föhr, and
Y Wahl, and
R Engling, and
T P Kemmer, and
M Gratzl
January 1991,
Cell calcium,
K J Föhr, and
Y Wahl, and
R Engling, and
T P Kemmer, and
M Gratzl
June 1989,
The Journal of biological chemistry,
K J Föhr, and
Y Wahl, and
R Engling, and
T P Kemmer, and
M Gratzl
August 1989,
The Biochemical journal,
K J Föhr, and
Y Wahl, and
R Engling, and
T P Kemmer, and
M Gratzl
February 1988,
FEBS letters,
K J Föhr, and
Y Wahl, and
R Engling, and
T P Kemmer, and
M Gratzl
April 2003,
Nihon yakurigaku zasshi. Folia pharmacologica Japonica,
K J Föhr, and
Y Wahl, and
R Engling, and
T P Kemmer, and
M Gratzl
January 1983,
Nature,
K J Föhr, and
Y Wahl, and
R Engling, and
T P Kemmer, and
M Gratzl
April 1994,
The Journal of biological chemistry,
K J Föhr, and
Y Wahl, and
R Engling, and
T P Kemmer, and
M Gratzl
February 1997,
Tanpakushitsu kakusan koso. Protein, nucleic acid, enzyme,
