Oyama Y, Chikahisa L, Noda K, Hayashi H, Tomiyoshi F
Department of Health Science, Faculty of Integrated Arts and Sciences, University of Tokushima, Japan.
Jpn J Pharmacol. 1992 Nov;60(3):159-67. doi: 10.1254/jjp.60.159.
The properties of triphenyltin (TPT) in increasing intracellular Ca2+ ([Ca2+]i) of thymocytes was studied, in comparison with those of A23187, by the use of fluorescent dyes to monitor membrane potential and [Ca2+]i. Both 1 microM TPT and 30 nM A23187 increased the [Ca2+]i associated with the hyperpolarization mediated by Ca(2+)-dependent K+ conductance. The time course for the TPT-induced increase in the [Ca2+]i was much slower than that of A23187. When the external Ca2+ ([Ca2+]o) was removed, TPT produced a slight, but persistent, increase in the [Ca2+]i while A23187 caused only a transient increase in the [Ca2+]i. Reintroduction of Ca2+ to the external solution produced an increase in [Ca2+]i in both cases. Therefore, these results suggested that the increase in the [Ca2+]i of thymocytes induced by TPT and A23187 was dependent on the presence of [Ca2+]o and an intracellular Ca store. The potency of TPT in increasing the [Ca2+]i was greater than those of diphenyltin and monophenyltin, suggesting an involvement of the lipophilic property of organotins in increasing [Ca2+]i. The TPT-induced increase in the [Ca2+]i may be partly responsible for the toxicity of TPT on organs and/or organ systems.
利用荧光染料监测膜电位和细胞内钙离子浓度（[Ca2+]i），研究了三苯基锡（TPT）与A23187相比，在增加胸腺细胞内[Ca2+]i方面的特性。1 microM的TPT和30 nM的A23187均可增加与Ca(2+)依赖性钾离子电导介导的超极化相关的[Ca2+]i。TPT诱导的[Ca2+]i增加的时间进程比A23187慢得多。当去除细胞外钙离子（[Ca2+]o）时，TPT使[Ca2+]i产生轻微但持续的增加，而A23187仅使[Ca2+]i产生短暂增加。在两种情况下，将钙离子重新引入细胞外溶液均会导致[Ca2+]i增加。因此，这些结果表明，TPT和A23187诱导的胸腺细胞[Ca2+]i增加依赖于[Ca2+]o的存在和细胞内钙库。TPT增加[Ca2+]i的效力大于二苯基锡和单苯基锡，表明有机锡的亲脂性在增加[Ca2+]i中起作用。TPT诱导的[Ca2+]i增加可能部分导致了TPT对器官和/或器官系统的毒性。
