Cytotoxic Action of Triphenyltin on Mouse Thymocytes: A Flow-Cytometric Study Using Fluorescent Dyes for Membrane Potential and Intracellular Ca²⁺

Abstract

Effects of triphenyltin on mouse thymocytes were examined using fluorescent dyes to monitor membrane potential and intracellular Ca²⁺. Triphenyltin at 3 × 10^-7 M to 1 × 10^-6 M hyperpolarized thymocytes and depolarized them at 3 × 10^-6 M or more, associated with increasing intracellular Ca²⁺. Hyperpolarization was suppressed by quinine, but not by tetraethylammonium and 4-aminopyridine, suggesting the involvement of Ca²⁺-activated K⁺ current. Triphentyltin failed to hyper-polarize thymocytes in Ca²⁺-free solution. Results indicate that triphenyltin promotes Ca²⁺-influx to thymocytes. Such an action of triphenyltin may be related to the immunotoxicity of organotins.