2,5-Di-(tert-butyl)-1,4-benzohydroquinone mobilizes inositol 1,4,5-trisphosphate-sensitive and -insensitive Ca2+ stores.
In permeabilized rat hepatocytes a maximal concentration (25 microM) of 2,5-di-(tert-butyl)-1,4-benzohydroquineone (tBuBHQ) mobilized 70% of sequestere Ca2+ and a half-maximal effect was produced by 1.7 microM tBuBHQ. Inositol 1,4,5-trisphosphate (Ins(1,4,5)P3) stimulated release of about 40% of the intracellular Ca2+ stores. Combined applications of a range of tBuBHQ concentrations with a maximal concentration of Ins(1,4,5)P3 demonstrated that tBuBHQ has slight selectivity for the Ca2+ transport process of the Ins(1,4,5)P3-sensitive stores. We conclude that the Ins(1,4,5)P3-sensitive stores are a subset of those sensitive to tBuBHQ and that the latter is therefore unlikely to prove useful as a tool to discriminate Ins(1,4,5)P3-sensitive and -insensitive Ca2+ stores though it may provide opportunities to design more selective agents.
Oldershaw
K A
KA
Department of Pharmacology, Cambridge, UK.
Taylor
C W
CW
D000818:Animals; D000975:Antioxidants / Q000494:pharmacology; D002118:Calcium / Q000378:metabolism*; D002463:Cell Membrane Permeability; D002478:Cells, Cultured; D006873:Hydroquinones / Q000494:pharmacology*; D015544:Inositol 1,4,5-Trisphosphate / Q000494:pharmacology*; D015759:Ionomycin / Q000494:pharmacology; D007700:Kinetics; D008099:Liver / Q000187:drug effects / Q000378:metabolism*; D051381:Rats
D000975:Antioxidants; D006873:Hydroquinones; C019359:2,5-di-tert-butylhydroquinone; D015759:Ionomycin; D015544:Inositol 1,4,5-Trisphosphate; D002118:Calcium