Komori S, Itagaki M, Unno T, Ohashi H
Department of Veterinary Science, Faculty of Agriculture, Gifu University, Japan.
Eur J Pharmacol. 1995 Apr 24;277(2-3):173-80. doi: 10.1016/0014-2999(95)00072-s.
To characterize intracellular Ca2+ stores, the Ca(2+)-releasing effects of caffeine, carbachol and inositol 1,4,5-trisphosphate (IP3) were compared by measuring the drug-induced tension development in beta-escin-skinned longitudinal smooth muscle of guinea-pig ileum. Caffeine (20 mM), carbachol (10 or 100 microM) or IP3 (40 microM), applied after loading Ca2+ within intracellular stores, produced a transient rise in tension in a Ca(2+)-free solution. This change in tension occurred in response to release of Ca2+ from the stores. The effect of either caffeine or carbachol was markedly reduced or abolished after preceding application of the other drug. IP3 was without effect when applied subsequently to caffeine. The effects of carbachol and IP3 were abolished after combined treatment with ryanodine (30 microM) and caffeine (20 mM) which causes functional removal of caffeine-releasable Ca2+ stores, but not after combined treatment with ryanodine (30 microM) and carbachol (10 microM). The results suggest that caffeine, carbachol and IP3 all act on common Ca2+ stores to release Ca2+.
为了表征细胞内钙库，通过测量豚鼠回肠β-七叶皂苷去皮纵向平滑肌中药物诱导的张力变化，比较了咖啡因、卡巴胆碱和肌醇1,4,5-三磷酸（IP3）的钙释放效应。在细胞内钙库加载钙离子后，施加咖啡因（20 mM）、卡巴胆碱（10或100 μM）或IP3（40 μM），在无钙溶液中产生张力的短暂升高。这种张力变化是由于钙库中钙离子的释放引起的。在预先应用另一种药物后，咖啡因或卡巴胆碱的作用明显减弱或消除。IP3在随后应用咖啡因时无效。在用ryanodine（30 μM）和咖啡因（20 mM）联合处理导致可被咖啡因释放的钙库功能去除后，卡巴胆碱和IP3的作用被消除，但在用ryanodine（30 μM）和卡巴胆碱（10 μM）联合处理后则没有。结果表明，咖啡因、卡巴胆碱和IP3均作用于共同的钙库以释放钙离子。
