Effect of tri-n-butyltin on intracellular Ca2+ concentration of mouse thymocytes under Ca(2+)-free condition.
Effect of tri-n-butyltin at concentrations ranging from 100 nM to 1 microM on the intracellular Ca2+ concentration of mouse thymocytes was examined under Ca(2+)-free conditions in comparison with those of 50 nM A23187, 100 nM thapsigargin and 10 microM cyclopiazonic acid, using the fluorescent dye for intracellular Ca2+, fluo-3. Tri-n-butyltin persistently increased the intensity of fluo-3 fluorescence while A23187, thapsigargin and cyclopiazonic acid produced a transient augmentation of the fluorescence. Pretreatment with A23187 greatly decreased the fluorescence responses induced by 1 microM tri-n-butyltin. However, the effect of thapsigargin and cyclopiazonic acid on the tri-n-butyltin-induced response was much weaker than that of A23187. In the presence of tri-n-butyltin, the transient response produced by A23187 was greatly prolonged. Results may suggest that tri-n-butyltin increases the membrane Ca2+ permeability of the intracellular organelles (cellular calcium stores) and decreases the Ca2+ pump activity of thymocyte membrane, resulting in a sustained increase in the intracellular Ca2+ concentration under Ca(2+)-free concentration.
Oyama
Y
Y
Laboratory of Cell Signalling (Pharmacology), Faculty of Integrated Arts and Sciences, University of Tokushima, Japan.
Ueha
T
T
Hayashi
A
A
Chikahisa
L
L
D000814:Aniline Compounds; D000818:Animals; D000001:Calcimycin / Q000494:pharmacology; D002118:Calcium / Q000378:metabolism* / Q000502:physiology; D000252:Calcium-Transporting ATPases / Q000037:antagonists & inhibitors; D005456:Fluorescent Dyes; D066298:In Vitro Techniques; D007211:Indoles / Q000494:pharmacology; D051379:Mice; D008815:Mice, Inbred Strains; D013050:Spectrometry, Fluorescence; D013601:T-Lymphocytes / Q000187:drug effects / Q000378:metabolism*; D013729:Terpenes / Q000494:pharmacology; D019284:Thapsigargin; D014220:Trialkyltin Compounds / Q000494:pharmacology*; D014966:Xanthenes
D000814:Aniline Compounds; D005456:Fluorescent Dyes; D007211:Indoles; D013729:Terpenes; D014220:Trialkyltin Compounds; D014966:Xanthenes; C059715:Fluo-3; D000001:Calcimycin; C011559:tributyltin; D019284:Thapsigargin; D000252:Calcium-Transporting ATPases; D002118:Calcium; C000543:cyclopiazonic acid